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Potential Chicken Health Challenges

red hen
Photo: Jo-Anne McArthur / We Animals Media

This resource has been fully reviewed and updated by a member of The Open Sanctuary Project’s staff as of March 15, 2022

Unfortunately for the humans looking out for them, chickens tend to hide signs of illness and injury until they are no longer able to do so. In order to catch and respond to health issues as early as possible, you’ll need to spend a lot of time observing and getting to know your residents so you are better able to catch less obvious signs of concern. By conducting regular full body health examinations, you’ll be able to know what healthy looks and feels (and smells!) like, and when you should be concerned. Check out our guide to chicken health examinations to familiarize yourself with the signs that something may be amiss with a chicken resident. For more information on health challenges that commonly affect chicks, check out our resource here.

Animal Healthcare Disclaimer

This is not an exhaustive list of everything that can happen to a chicken, but can help you get a sense of what challenges a chicken under your care may face in their lifetime. If you believe a chicken is facing a health issue, always discuss with a qualified veterinarian as soon as possible. Reading about health issues does not qualify you to diagnose your residents!

Issues By Body System

Circulatory: Heat Exhaustion, Heart Problems

Gastrointestinal: Coccidiosis, Crop Impaction, Fowl Cholera, Newcastle Disease, Sour Crop (Candidiasis), Worms

Immune: Avian Leukosis Virus (Lymphoid Leukosis), Reticuloendotheliosis

Musculoskeletal: Arthritis (Osteoarthritis and Septic Arthritis), Bumblefoot, Fowl Cholera, Gout, Osteomyelitis, Wing Fractures

Neurological: Avian Influenza, Botulism, Marek’s Disease, Newcastle Disease

Reproductive: Avian Influenza, Cystic Right Oviduct, Egg Binding (Egg Bound), Egg Yolk Peritonitis/ Coelomitis, Impacted Oviduct, Infectious Bronchitis, Internal Laying, Prolapsed Vent, Salpingitis, Soft-Shelled Eggs, Reproductive Tract Cancer (Ovarian or Oviductal)

Respiratory: Aspergillosis, Avian Influenza, Fowl Cholera, Fowl Pox, Gapeworm, Infectious Bronchitis, Infectious Coryza, Infectious Laryngotracheitis (ILT), Mycoplasma, Newcastle Disease

Urinary: Gout, Infectious Bronchitis

Skin And Feathers: Fowl Pox, Flystrike, Lice, Mites, Molting, Scaly Leg Mites

Eyes And Ears: Fowl Cholera, Marek’s Disease

Arthritis

Chickens can develop various mobility issues, including osteoarthritis (also called degenerative joint disease) and septic arthritis (also called infectious arthritis). While any breed of chicken can develop arthritis, both types are especially common in large breed chickens.

Osteoarthritis– This type of arthritis is often associated with advanced age, though it can also occur in younger individuals as well, especially large breed chickens who are overweight. Signs of osteoarthritis include abnormal gait, bearing weight unevenly when standing, lameness, and reduced activity. You may be able to hear or feel crepitus (grating or crunching) in the hock (this can be more difficult to feel in the knee and hip). Chickens with osteoarthritis may spend more time lying down. Ensuring large breed chickens remain at a healthy weight can help prevent, or delay, osteoarthritis, but even chickens who are at a healthy weight could develop this condition. Treatment with analgesics and creating a living space that is easy for arthritic chickens to navigate can help keep residents comfortable.

Septic Arthritis- Septic arthritis is inflammation of the joint(s) due to introduction of an infectious agent, which may result following septicemia or a localized infection of the joint. Large breed chickens appear to be more prone to septic arthritis than other chickens. In some cases, the joint may be red, swollen, hot, and possibly open and oozing. However, in other cases, there may not be obvious outward signs of infection, such as heat or significant swelling, and the chicken may look like they have a non-infectious mobility issue. Be sure to work closely with your veterinarian if a resident is showing signs of mobility issues and to discuss the possibility of septic arthritis. While your veterinarian may decide to tap the joint during their physical evaluation, this should not be attempted by anyone other than a veterinary professional- doing so could introduce bacteria into the joint and/or damage the internal structures of the joint, causing further issues. A veterinary diagnosis is imperative. Caregivers sometimes confuse clinical signs of gout with infection, and the two conditions require different treatments, so be sure to work closely with your veterinarian. There are numerous pathogens that can cause septic arthritis, with Staphylococcus aureus being the most common. Other potential causes include Escherichia coli and Mycoplasma synoviae. Septic arthritis can be difficult to treat and typically requires prolonged systemic antibiotic treatment along with analgesics. Regional limb perfusion or the use of antibiotic-soaked gauze or impregnated beads may be recommended to deliver the antibiotics to the infected joint. Septic arthritis can cause permanent joint damage and predispose the individual to degenerative joint disease. Even following resolution of the infection, the individual may continue to have mobility issues and may require ongoing analgesics.

SOURCES:

Geriatric Diseases of Pet Birds | Merck Veterinary Manual

Noninfectious Skeletal Disorders in Poultry Broilers | Merck Veterinary Manual (Non-Compassionate Source)

Prevalence  of  Septic  Arthritis  Caused  By  Staphylococcus  aureus  In  Poultry Birds At Tandojam, Pakistan | Journal Of Animal Health And Production (Non-Compassionate Source)

Mycoplasma Synoviaeand Other Associated Bacteria Causing Arthritis in Chicken | Tawfik, Khalil, Ellakany, Torky (Non-Compassionate Source)

Staphylococcosis in Poultry | Merck Veterinary Manual (Non-Compassionate Source)

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Aspergillosis

Aspergillosis is a non-contagious fungal disease that typically manifests as respiratory illness in birds. While there are numerous species of Aspergillus that can cause aspergillosis, Aspergillus fumigatus, a ubiquitous soil fungus, is the most common cause in chickens, turkeys, ducks, and geese. Aspergillosis is an opportunistic infection- while birds are constantly exposed to fungal spores, often without developing disease, immunosuppression (such as from stress, corticosteroid use, disease, or malnutrition) and being exposed to large numbers of aerosolized spores may result in disease. Poor ventilation, unsanitary conditions, wet bedding, moldy food, and warm, humid conditions increase the risk of aspergillosis. Therefore, you can help protect your residents by properly storing food, keeping living spaces clean and well ventilated, and ensuring spaces do not become warm and humid. Straw bedding can harbor mold and fungus, so wood shavings or other non-straw (and non-hay) bedding is a better option if aspergillosis is a concern. Aspergillosis typically causes acute signs in young birds (often called “brooder pneumonia”) and a more chronic condition in older birds. Signs of aspergillosis include open-mouth breathing, labored breathing, tail bobbing, gasping, and an elevated respiratory rate. Other signs include inappetence and lethargy. Be sure to contact your veterinarian if you suspect aspergillosis. Diagnosis can be challenging, so be sure to work with your veterinarian to see what diagnostics they recommend. Treatment is also challenging and often requires aggressive and prolonged antifungal treatment (such as itraconazole) as well as supportive care. In addition to treatment, be sure to take steps to reduce your residents’ exposure to spores by keeping living spaces dry, ensuring food and bedding are not wet or moldy, switching from straw to a safer bedding option, and improving ventilation.

SOURCES:

Aspergillosis | Niles Animal Hospital And Bird Medical Center

Mycotic Diseases of Pet Birds | Merck Veterinary Manual

Current Therapy In Avian Medicine And Surgery | Brian L. Speer

Diseases of Poultry 13th Edition | David Swayne (Non-Compassionate Source)

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Avian Influenza (Or, “Bird Flu”)

The term “avian influenza” refers to any disease or infection in birds that is caused by Type A influenza viruses. Free-flying aquatic birds (such as migratory waterfowl and shorebirds) are the natural host of Type A influenza viruses, but these viruses can also affect domesticated farmed birds and other bird species. To read more about avian influenza (AI) check out our resource here.

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Avian Leukosis Virus (Lymphoid Leukosis)

Avian Leukosis Virus (ALV), or Lymphoid Leukosis (LL), causes tumors in many organs of a chicken. Symptoms are very broad and non-specific and are similar to many less serious diseases. These symptoms include a lack of appetite, dehydration, diarrhea, general weakness, weight loss, a reduction in egg laying, and an enlarged liver or bursa. The virus can be transmitted vertically, from a mother to her chick through the albumin or egg yolk, and the chick can shed the disease for their entire life. It can also be spread horizontally, by fecal contamination. There is unfortunately no treatment for Avian Leukosis beyond supportive care. Mortality directly from the tumors is generally low; therefore, the disease can be present in your flock and can go unnoticed. There are six subgroups of this virus and they each can affect the bird differently. However, all strains have the ability to produce tumors. Development of tumors is more common in the vertical transmission but many more chickens are exposed via the horizontal route. Thankfully, the virus isn’t very hardy in the environment and can be eliminated by many common disinfectants. This is another good reason to have good biosecurity measures in place and good sanitation at your sanctuary. As with Marek’s Disease Virus, testing on live birds is difficult due to the virus being so widespread among flocks- virus detection tests have limited or no value in field testing conditions. The disease can be determined postmortem via advanced testing of the tissues.  

SOURCES:

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

Lymphoid Leukosis in Poultry | Merck Veterinary Manual( Non-Compassionate Source)

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Botulism

Botulism is more common in waterfowl, but can also occur in chickens. It is caused by ingestion of neurotoxins produced by the bacteria Clostridium botulinum. While this bacteria is found in the environment without causing issues, under certain conditions the bacteria multiplies and produces toxins. Common sources of these toxins are decaying vegetation and carcasses, as well as maggots feeding on decaying matter. Signs of botulism include progression from weakness to flaccid paralysis of legs, wings, neck, and eyelids. Botulism is sometimes called “limberneck” due to the neck paralysis associated with the disease. The feathers on the neck may also become loose and come out easily. The time between ingestion of the neurotoxin and onset of clinical signs, as well as the severity of those signs, is dependent on the amount of toxin ingested. High doses of toxin can result in clinical signs developing within hours, whereas clinical signs may take a few days to develop if lower doses are ingested. High levels of the toxin are lethal, resulting in respiratory paralysis. Treatment includes prompt administration of antitoxin and supportive care. If botulism is suspected, in addition to seeking urgent veterinary care, it is important to identify the source of the toxin and prevent residents from further access. Prevention includes keeping residents away from decaying foods and carcasses and ensuring they have ready access to fresh food and water.

SOURCES:

Botulism In Poultry | Poultry Extension

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

Botulism In Poultry | Merck Veterinary Manual (Non-Compassionate Source)

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Bumblefoot

Bumblefoot can affect all breeds of chickens but is especially common in large breed individuals. Bumblefoot can be caused by many different factors including environmental conditions (such as poor sanitation or rough flooring or perching materials) or physical conditions (such as obesity or arthritis). Individuals who favor one foot over the other, due to pain or a mechanical leg issue, may develop bumblefoot on their “good” side. Because this foot has to bear more weight, the skin can become damaged over time. Without proper interventions, bumblefoot can progress from a minor issue to something far more severe.

Bumblefoot is typically categorized as mild, moderate, or severe, with severe cases involving infection in the bone (osteomyelitis). The following 1-5 grading system gives a good overview of the progression of this disease and how it affects the overall prognosis, but be aware that your veterinarian may use a different grading system to evaluate and talk about bumblefoot.

Grade 1– At this stage, only the outer skin is affected. It may be very smooth (due to the loss of the small papilla normally present), and it may also be shiny and red, but there is no open wound or sign of infection. With proper interventions, prognosis at this stage is excellent.

Grade 2– At this stage, there is damage to the skin and there may be a scab, callous, or open wound, but the foot will not be obviously swollen. With proper interventions, prognosis at this stage is good.

Grade 3– At this stage, the disease process, and possibly infection, have progressed deeper into the tissues of the foot. The foot will be swollen and painful, and there may be discharge. Prognosis at this stage is good to guarded.

Grade 4– At this stage, the infection has progressed to involve deeper structures within the foot such as tendons and bone. Individuals with this stage of disease may develop tenosynovitis (inflammation of the tendon sheath), arthritis, and/ or osteomyelitis. Prognosis at this stage is guarded to poor.

Grade 5– At this stage, the condition is so severe that it results in debilitating deformity and loss of function. Prognosis at this stage is grave.

It is important to address bumblefoot early before it becomes actively infected and to prevent the introduction of bacteria by keeping the area clean and covered. Depending on the underlying cause, when caught early, foot wraps and changes to the environment may be enough to prevent progression if there is no infection. However, if the primary cause is osteoarthritis in the opposite limb, it can be difficult to fully resolve bumblefoot and have the skin of the foot completely heal.

Be sure to work with a veterinarian if one of your residents has bumblefoot, especially if the affected foot is warmer than normal, painful, or swollen, or if it has discharge, an open wound, or a large scab. Your veterinarian can assess the foot to determine how severe the condition is (which may require x-rays), prescribe appropriate medications, and help create a treatment plan. Depending on the severity, treatment may include systemic antibiotics, analgesics, soaking the foot, various types of foot wraps, delivery of antibiotics directly to the affected area (for example, through the use of antibiotic-impregnated beads), and in some cases, surgical debridement (done by a licensed veterinarian with appropriate analgesics and anesthetics). Keep in mind that the individual’s good foot may be vulnerable to developing bumblefoot if they are especially painful and reluctant to bear weight on the affected foot. Be sure to keep a close eye on the other foot and protect it with a padded bandage as needed.

It is important to work with a veterinarian to determine which structures of the foot are affected, to establish an appropriate treatment plan, and if the treatment involves wound management or wrapping the foot, you must be shown how to do this properly. Left untreated, bumblefoot infections can have devastating consequences.

SOURCES:

Geriatric Diseases of Pet Birds | Merck Veterinary Manual

Pododermatitis In Birds And Small Mammals | Schoemaker and Van Zeeland

Bumblefoot Surgery And Management | Great Western Exotic Vets

A Multifaceted Approach to the Treatment of Bumblefoot in Raptors | J. David Remple (Non-Compassionate Source)

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

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Coccidiosis

Coccidiosis in chickens refers to disease caused by the protozoal parasites Eimeria spp. While chickens of all ages can become infected, disease is most often seen in younger chicks. Individuals who have a weakened immune system due to disease or stress are also at an increased risk of developing coccidiosis. Eimeria oocysts are spread in the feces of infected chickens, which can result in contamination of food, water, soil, and bedding. Oocysts can also be spread by mechanical means on shoes, equipment, and other fomites. After being shed in the feces, oocysts sporulate and become infective. Other chickens become infected by ingesting infective oocysts, with clinical disease occurring in susceptible individuals who ingest relatively large numbers of infective oocysts. There are nine species of Eimeria that affect chickens, and following infection, the chicken develops protective immunity against the particular species of Eimeria they were exposed to. Signs of coccidiosis in chickens include diarrhea, bloody feces, loss of appetite, weight loss, ruffled feathers, and huddling together for warmth. Eimeria oocysts can be detected via a fecal float. If Eimeria are detected on a routine fecal examination and the individual is not showing signs of clinical disease, we recommend consulting with your veterinarian about whether or not treatment is necessary. Coccidiosis is self-limiting and treatment may not be recommended; however, individuals showing clinical signs of disease may require treatment as prescribed by your veterinarian. You can reduce your residents’ exposure to Eimeria oocysts by properly quarantining new residents, regularly removing feces and soiled bedding from living spaces, and by keeping food and water sources clean.

SOURCES:

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

Diseases of Poultry 13th Edition | David Swayne (Non-Compassionate Source)

Overview Of Coccidiosis In Poultry | Merck Veterinary Manual (Non-Compassionate Source)

Overview Of Coccidiosis | Merck Veterinary Manual (Non-Compassionate Source)

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Crop Impaction

If a crop is not able to properly empty due to any degree of blockage, it will become impacted.  Crop impactions can be caused by a variety of factors. In some cases, birds will ingest materials that are not digestible such as feathers, long blades of grass, straw, wood shavings, foreign objects, or kitty litter.  Another cause, and one that is typically seen in large breed chickens, is crop impaction resulting from gorging on large quantities of food. In some cases, the crop is not able to properly empty due to damage or disease, and crop impactions can also be secondary to another disease such as Marek’s or intestinal thickening.  In addition to offering treatment, it’s important to also identify to underlying cause. In severe cases, a crop may need to be surgically emptied, and in some cases, most of the crop muscle may need to be removed. In more mild cases, your veterinarian may prescribe drugs that improve crop motility or flushing and massaging of the crop (this must be demonstrated by a professional as flushing the crop incorrectly can result in aspiration and death).

SOURCE:

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

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Cystic Right Oviduct

In chickens, like most other species of birds, only the left ovary fully develops and is functional. The right oviduct regresses but can become fluid-filled. A large cystic right oviduct can contain a pint of fluid. This can compress a hen’s vital organs and put pressure on air sacs. Ultrasonography can confirm a suspected cystic right oviduct diagnosis. You can usually drain the fluid safely without surgery but you must consult an avian expert first as this is not always necessary, and you must be taught the proper technique to prevent causing complications such as infection or organ damage. Fluid build-up from a cystic right oviduct develops much more slowly than fluid build-up that is the result of reproductive tract cancer. Fluid is often clear in color but may be opaque and cloudy with visible floating particles present.

SOURCES:

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

Diseases of Poultry 13th Edition | David Swayne (Non-Compassionate Source)

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Egg Binding (Egg Bound)

A hen who is egg bound has an egg stuck in her oviduct. Typical signs of egg binding include obvious straining, squatting, standing up oddly tall, open-mouthed breathing (from the pain and stress of pushing), and a lack of appetite, though sometimes the only sign something is wrong is that they are isolating themselves or not quite acting like themself. Egg-binding can lead to cloacal prolapse, a potentially fatal condition. Do not cut the bird to get the egg out, or break the egg. In some instances, holding the chicken in a warm bath can help her to pass the egg.  However, this doesn’t always work, so watch the chicken closely, and if she does not pass the egg while in the bath, or if her symptoms worsen at all, take her to the veterinarian as soon as possible- if left untreated, egg-binding can be fatal. If you suspect a hen is egg bound but the chicken is not showing any of the more serious symptoms described above, you can place her in an area with a safe heat source such as a heating pad or snuggle safe heat disc- always have a towel or other fabric between the bird and the heat source, make sure the space is set up so that the chicken can move away from the heat source if needed, and also make sure that they are well enough to move themselves away from the heat if desired. Talk to your veterinarian about providing an oral vitamin and probiotic supplement made specifically for chickens and adding additional oral calcium to their diet during this time. If, over the course of the next 24 hours, the hen has not passed an egg or if she becomes progressively painful, she should be examined by a veterinarian. 

SOURCES:

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

Diseases of Poultry 13th Edition | David Swayne (Non-Compassionate Source)

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Egg Yolk Peritonitis/ Coelomitis

Peritonitis is inflammation of the peritoneum (the membrane that lines the abdominal cavity). Egg Yolk Peritonitis (also called EYP or Egg Peritonitis) occurs when there is egg material present in a chicken’s abdomen causing the inflammation. Egg material can enter the abdomen in various ways, either from being released from the ovary directly into the abdomen, by being expelled back out of the oviduct for some reason, or from a ruptured oviduct (often due to a severe oviductal impaction). Bacteria quickly grow in the resultant environment. This is an unfortunately common disease in breeds used in industrial egg production, but can affect females of any breed, including large breed chickens, and typically does not end well if left untreated. Depending on the underlying cause of the inflammation/infection, it is not uncommon for the bird to make a full recovery with appropriate treatment, especially if there was not an underlying infectious process causing the issue. On a veterinarian’s recommendation, Egg Yolk Peritonitis can be treated with intervention (draining of abdominal fluid), antibiotics, anti-inflammatories, and potentially Suprelorin implantation to give them time to recover, though prognosis is highly dependent on what caused the egg material to end up in their abdomen in the first place. If abdominal fluid is collected, it can be cultured to identify bacterial causes and to determine what drugs the bacteria are susceptible to. It’s a good idea to request a complete blood panel if egg yolk peritonitis is suspected.

SOURCES:

Coelomitis In Birds | Brian Speer, DVM, DABVP (Avian Practice), DECZM (Avian) Medical Center For Birds

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

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Flystrike

Flystrike refers to the presence of maggots, typically in a wound.  There are various degrees of severity of flystrike, and the quicker you catch and treat the issue, the better.  Though mild cases of flystrike aren’t likely a health emergency, it is imperative to remove the maggots immediately and address what attracted the flies in the first place (broken egg yolk or clumps of feces on feathers or an open wound).  Often you will find flystrike in or near the vent. If maggots appear to be in the vent or burrowed deeply into the body (likely in the case of advanced flystrike), you should bring the bird to the veterinarian to be assessed and to ensure all maggots are removed. A safe and effective way to kill maggots in a bird suffering from flystrike is to dissolve a tab of Capstar in a syringe of water and then spray the dissolved Capstar onto the affected area.  However, manual removal of the maggots is often the most efficient way to treat this issue. Unless the flystrike was caused by something easily remedied like a bird covered in broken egg who simply needs to be cleaned off, keep the chicken indoors until the underlying issue has resolved. Consult with your veterinarian about administering antibiotics or pain medications based on the severity of the issue.

SOURCE:

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

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Fowl Cholera

Caused by Pasteurella multocida, fowl cholera is a contagious bacterial disease that can affect both wild and domesticated bird species, including turkeys, ducks, geese, and chickens. Of these species, chickens are the least susceptible, though some breeds are more susceptible than others and older chickens are more susceptible than younger chickens. Fowl cholera typically occurs in late summer, fall, or winter, and can manifest as acute, chronic, or asymptomatic infection. Acute infection is often fatal, and unfortunately, signs of illness usually only manifest a few hours before death. Signs of acute fowl cholera include fever, inappetence, increased respiratory rate, puffy feathers, and oral mucous discharge. Cyanosis is typically seen at the end stages. Individuals will also have diarrhea, which starts out whitish and watery and later contains mucous and turns a greenish color. Individuals who survive an acute infection may remain chronically infected. P. multocida strains with low virulence may cause chronic infection without acute infection. Signs of chronic infection may include swelling of the sinuses, wattles, foot pads, along the keel, or in the joints of the wing or legs. If infection in the ear occurs, the individual may develop torticollis (wry neck). Respiratory infection may cause open-mouth breathing and tracheal rales. P. multocida can be introduced to a flock by an asymptomatic or chronically infected individual, but it’s also possible for wild birds to transmit this infection to sanctuary residents if they are able to come into contact with one another. While some mammalian farmed animal species can be carriers of P. multocida, according to Diseases of Poultry, 13th Edition, these organisms do not typically cause disease in chickens, with the exception of P. multocida from pigs. Infected individuals spread the bacteria in discharge from the eyes, nares, or mouth, which then contaminates the environment as well as food and water sources. The bacteria can also be spread in feces of infected birds. Contact your veterinarian right away if you suspect a resident has fowl cholera. Diagnosis is confirmed with bacterial culture. Your veterinarian can recommend treatment, but successful treatment is dependent on how early and aggressively treatment is initiated and whether or not other infections are present. There are vaccines available, but these do not offer complete protection. Be sure to talk to your veterinarian about whether or not vaccination is recommended and which vaccine is most appropriate. The bacteria can be killed by sunlight, heat, drying, and common disinfectants. 

SOURCES:

Diseases of Poultry 13th Edition | David Swayne (Non-Compassionate Source)

Fowl Cholera | Merck Veterinary Manual (Non-Compassionate Source)

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Fowl Pox

There are two forms of fowl pox, the dry form and the wet form, and chickens can be affected by just one form or by both at the same time. Dry, or cutaneous, pox causes raised scabs and wart-like lesions on non-feathered parts of the chicken, but especially on the face, comb, and wattles. These lesions can easily be mistaken for fighting injuries. This form of pox generally does not make birds clinically ill; however, the lesions can be painful and lesions on or near their eyelids can result in damage to the eye. Keeping lesions clean and covered with an antibiotic ointment can help prevent secondary infections. Use caution around eyes- it may be best to use an antibiotic eye ointment for lesions on or near the eyelid. Dry pox typically resolves on its own. Wet, or diphtheritic, pox can cause lesions and canker-like growths in the mouth and upper airway. Wet pox can cause respiratory distress from mechanical blockage of the airway by these lesions and can also develop into issues lower down the respiratory tract in the air sacs and lungs. Fowl pox is a viral disorder that is transmitted through direct contact between birds and also through mosquitoes. The scabs contain the virus and will spread the disease when they fall off. There is no definitive treatment for fowl pox. If you suspect that one of your chicken residents is suffering from the wet form of pox, we strongly recommend you contact your veterinarian. Thankfully, fowl pox is relatively slow spreading. There is an attenuated (live) vaccine available that is administered with a double-pronged wing stick that can help prevent the spread of the disease, but anecdotally, some sanctuaries who have used this vaccine have noted that some of their older residents, especially Cornish crosses, appeared to have adverse reactions from the vaccine. If you have residents with fowl pox, you should discuss the risks and benefits of vaccination with your veterinarian. 

SOURCES:

Fowl Pox In Chickens And Turkeys | Merck Veterinary Manual 

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

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Gapeworm (Syngamus trachea)

Gapeworm is a parasitic nematode that can cause respiratory illness in chickens.  Gapeworms migrate to the chicken’s tracheal mucosa layer where they feed off the chicken’s blood and reproduce.  This attachment leads to nodules and inflammation in the trachea and sometimes can then result in pneumonia. Occasionally, as the worms multiply, they begin to block the chicken’s trachea and severe infestations can cause the chicken to suffocate.  Chickens with gapeworm are often seen extending their necks, shaking their heads, and gasping for air (or gaping). In some instances, you might even be able to see the worms if you look down the chicken’s throat.  Chickens can be exposed to gapeworm through other infected birds who cough them up into the environment and shed the eggs in their feces (after coughing up eggs and then swallowing them), but they can also become infected by ingesting earthworms, slugs, snails, or flies who are intermediate hosts.  Chickens presenting clinical signs of gapeworm can be tested with a fecal float, but your veterinarian may recommend starting treatment before the fecal results are back. Smaller chicken breeds tend to be more severely affected by the clinical signs of infestations. Gapeworm infestations can be treated with certain dewormers including the avermectin family (ivermectin, moxidectin, etc.) and the benzimidazole family (fenbendazole, oxfendazole, albendazole, etc.) or a combination of the above mentioned.  There are also some other families of de-wormers that are effective against gapeworms, your veterinarian will best advise you. Chickens with severe clinical signs should be seen by a veterinarian even if it is confirmed to be a gapeworm infestation- chickens with heavy parasite loads could require additional treatment to prevent suffocation as the worms die off. Because infected chickens spread gapeworm eggs in the environment and because intermediate hosts such as earthworms can spread infection, you may need to rotate pastures and till the soil once the birds have been removed or restrict the flock’s access to contaminated outdoor spaces to prevent reinfection.

SOURCES:

Session 3: Respiratory, Neurological And Musculo-Skeletal Diseases | Backyard Poultry Online ‘Mini Series’

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

Helminthiasis in Poultry | Merck Veterinary Manual (Non-Compassionate Source)

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Gout

Gout is caused by hyperuricemia, an excess of uric acid in the blood, which can develop if a chicken produces more uric acid than their kidneys can excrete or if they have kidney issues that impair their ability to excrete uric acid normally. This results in uric acid deposits within the body. There are two forms of gout that affect chickens- visceral and articular gout. 

Visceral Gout– Chickens with visceral gout develop uric acid deposits around their visceral organs. Common areas affected include the liver, spleen, and pericardium. Possible signs of visceral gout include lethargy, poor appetite, weight loss, ruffled feathers, and abnormal droppings. However, individuals with visceral gout may die suddenly without showing obvious clinical signs and a diagnosis of visceral gout may be made during a post-mortem examination.

Articular Gout– Chickens with articular gout develop uric acid buildup in their joints, typically in their feet, resulting in soft, painful swelling. Articular gout is sometimes mistaken for bumblefoot, but a key difference is that swelling from articular gout will not be hot. Your veterinarian may take a sample of the material for diagnostic purposes, but you should not attempt to drain affected areas yourself. According to Dr. M. Scott Echols, DVM, Dipl ABVP-Avian, though uncommon, articular gout without underlying kidney disease appears to be hereditary.

Individuals showing any of the signs listed above should be seen by a veterinarian for evaluation. There are a variety of factors that can contribute to the development of gout, including dietary-related issues (ex. prolonged vitamin A deficiency, excess dietary calcium, diets with excessively high levels of protein), infectious diseases that result in kidney damage (ex. infectious bronchitis, avian nephritis virus), and toxins (ex. mycotoxins, certain antibiotics, overdose of insecticides or disinfectants). Your veterinarian can recommend further diagnostics and appropriate treatment which may include fluid therapy, medications to manage hyperuricemia (such as allopurinol and colchicine), and possible dietary changes and/ or supplementation (such as with vitamin A). Treatment will depend on the specific situation, so be sure to defer to your veterinarian. In the case of articular gout, your veterinarian may also recommend surgery. This is a painful procedure that can result in profuse bleeding and secondary infection and should only be done by a licensed veterinarian using appropriate anesthetics and analgesics.

SOURCES:

Avian Renal Disease: Pathogenesis, Diagnosis, And Therapy | Michael Lierz, Dr. Med. Vet.

Evaluating And Treating The Kidneys | M. Scott Echols, DVM, Dipl ABVP- Avian

Gout Management in Poultry | The Poultry Site (Non-Compassionate Source)

Avian Urolithiasis (Visceral Gout): An Overview | The Poultry Site (Non-Compassionate Source)

Pathology Of Visceral Gout In Layer Chicken | Lakshmi Namratha M, Y Ravi Kumar, And M Lakshman (Non-Compassionate Source)

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Heat Exhaustion

When it’s hot out, be sure to monitor chickens closely for symptoms of heat exhaustion, especially large breed chickens who are more prone to heat-related illness. During warm weather, you must implement appropriate strategies to keep indoor living spaces cool and offer other opportunities for residents to get relief from the sun and heat. It’s important to note that as humidity rises, the temperature at which a chicken is likely to develop heat-related illness lowers. Therefore, the most dangerous times for chickens are periods of high humidity and high temperatures.

It’s important to watch for signs that a chicken is too warm, and make adjustments to their living space BEFORE the condition progresses to dangerous heat exhaustion. A chicken who is too hot, but not yet suffering from heat exhaustion, will stand with their wings held away from their body and will breathe with their mouth open. As the condition progresses, what starts as slight open-mouth breathing will become more exaggerated panting, possibly with their neck extended, and their respiratory rate will increase. Their comb and wattles may become pale, they may develop diarrhea, and will appear lethargic. In advanced stages, the chicken may collapse or even have seizures.

Call your veterinarian immediately if one of your residents appears to be suffering from heat exhaustion. It’s important to gradually lower their body temperature- this can be done by moving them out of the sun (but keep handling to an absolute minimum), misting their feet and legs with cool, but not ice-cold, water, and positioning a fan to cool them off. In addition to cooling them off, your veterinarian will be able to advise you about how to safely address their dehydration and possible electrolyte imbalance and may also recommend other treatments, including antibiotics to address secondary immunosuppression and bacterial translocation.

SOURCES:

Research Note: Evaluation Of A Heat Stress Model To Induce Gastrointestinal Leakage In Broiler Chickens | Poultry Science (Non-Compassionate Source)

The Effect Of Heat Stress On Intestinal Integrity And Salmonella Invasion In Broiler Birds | Journal Of Thermal Biology (Non-Compassionate Source)

How To Spot Signs And Prevent Heat Stress In Chickens | VPSI (Non-Compassionate Source)

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Heart Problems

While any breed of chicken can develop heart disease, large breed chickens are more prone to heart failure than other breeds, with Cornish crosses typically being more at risk than other large breed chickens who grow more slowly (such as a Red Ranger or other colored hybrid). Two manifestations of heart failure that are commonly discussed in regards to large breed chickens are Sudden Death Syndrome (SDS, sometimes called Flip-over Disease) and Ascites Syndrome.

Like humans, chickens can experience acute or chronic heart failure. With acute heart failure, chickens often die without showing obvious outward signs of concern ahead of time (hence the name Sudden Death Syndrome). However, chickens who die from acute heart failure often have a history of arrhythmia. Cardiac arrhythmia and SDS are more common in male large breed chickens than females, though both sexes can be affected. Chickens as young as a week old can develop cardiac arrhythmia, but this issue becomes more common as chickens age. Stress can also play a role in SDS, with stressful events sometimes triggering arrhythmia in individuals with heart issues.

While the incidence of cardiac arrhythmia in non-large breed chickens is less than 1%, arrhythmias can be as high as 27% in Cornish crosses who are free-fed. However, the incidence of cardiac arrhythmia may be reduced to less than 2% when large breed chickens are kept on a restricted diet (yet another reason why it is so important to make sure large breed chickens are fed an appropriate diet and maintained at a healthy weight).

There are varying degrees of chronic heart failure in chickens. In mild cases, the most common sign is hypoxemia (low blood oxygen). Many chickens develop pericardial effusion (build-up of fluid around the heart) and ascites (build-up of abdominal fluid) as the condition progresses. The incidence of ascites is highest in large breed chickens who are free-fed.

In addition to ascites, signs of heart issues to be on the lookout for include a darkening of the comb and wattles (which may be more common in colder weather or times of stress) and wet, gurgly breathing (especially when stressed). All of these signs could be the result of another health issue, especially a respiratory issue, so it’s important to work closely with your veterinarian to make a diagnosis. However, large breed chickens with heart issues can be more sensitive to stress which can make transport to the veterinarian and a physical exam or other diagnostics challenging. Be sure to discuss the best course of action for your resident birds with your veterinarian. If your veterinarian is able to do an onsite exam, there are tools that they could use to do an electrocardiogram with a smart phone, which could then be evaluated by a specialist. Depending on the issue at hand, there are medications that can be used such furosemide (a diuretic), enalapril (an ACE inhibitor), and pimobendan (an inodilator). However, if the individual becomes very stressed with handling and medicating, you’ll need to weigh the risks and benefits of medications.

While large breed chickens may be more likely to suffer from heart failure than other chickens, the evidence shows that you can greatly reduce this risk by maintaining your residents at a healthy weight.

SOURCE:

Pathophysiology Of Heart Failure In Broiler Chickens: Structural, Biochemical, And Molecular Characteristics | Olkowski, A.A. (Non-Compassionate Source)

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Infectious Bronchitis

Infectious bronchitis is a highly contagious upper respiratory disease caused by an avian coronavirus, infectious bronchitis virus (IBV). Infected chickens shed IBV in their respiratory discharges, and respiratory aerosols play a significant role in transmission. The virus is also shed in the feces of infected chickens. Other chickens become infected by inhaling or ingesting virus particles through direct or indirect contact with infected chickens. Contaminated food and water, as well as equipment, clothing, and other fomites also play a role in transmission. Morbidity typically reaches 100%, but the severity of the disease depends on many factors including the strain of the virus, age of the individual, immune status, presence of co-infections, and environmental factors such as air quality and temperature. IBV infection can make chickens more vulnerable to secondary respiratory infections and can worsen primary respiratory infections. Some strains of IBV affect the kidneys, and these strains tend to have the highest mortality rates, particularly in chicks. Signs of IBV infection include coughing, sneezing, and abnormal breathing sounds. Chickens may look sick, with puffed-up feathers, and may be reluctant to move. Hens who are actively laying may show a decrease in egg laying and/or lay eggs with poor shell quality. Contact your veterinarian if your residents are showing signs of infectious bronchitis. Diagnostic testing is necessary to confirm. There is no specific treatment for infectious bronchitis. However, since cold stress and poor air quality can make the outcome worse, being sure to provide warmth, ventilation, and healthy air quality can help. Additionally, your veterinarian may prescribe treatment to address bacterial infections that can complicate infectious bronchitis. Supportive care may also be necessary. If chickens are infected with a strain that causes kidney issues, decreasing protein levels and providing electrolytes may be beneficial.

SOURCES:

Infectious Bronchitis In Poultry | Merck Veterinary Manual (Non-Compassionate Source)

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

Diseases of Poultry 13th Edition | David Swayne (Non-Compassionate Source)

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Infectious Coryza

This is a bacterial infection that causes an acute respiratory disease that presents with nasal discharge, coughing, sneezing, and swelling of the face. You may notice a foul-smelling odor to the breath and labored breathing. Mortality is relatively low but the birds can be sick for up to months at a time depending on the severity of the infection. It is transmitted directly from bird to bird through contact, inhalation of respiratory secretions from affected birds, contaminated food or water sources, or through contaminated clothing, equipment, or other fomites. Some birds can become healthy carriers of the disease. Sick birds can respond to proper antibiotic treatment, but recovered birds can become healthy carriers of the disease.

SOURCES:

Overview of Infectious Coryza in Chickens | Merck Manual (Non-Compassionate Source)

Infectious Coryza | Poultry Hub (Non-Compassionate Source)

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Infectious Laryngotracheitis (ILT)

Mature chickens are most commonly affected by this disease which is caused by a highly contagious herpes virus. The virus is easily transmitted from bird to bird by contact with infected birds and contaminated clothing or equipment. It is characterized by severe respiratory distress, coughing, and an audible rale from the chest. You may note some blood in the coughed up secretions. Some birds can die from suffocation if the coughed up mucus gets stuck in the airway. Generally, the most common thing noted in early stages of the infection is watery eyes. Testing can be performed by your veterinarian. Controlling this disease is done by isolating and treating affected birds. Good biosecurity is also important. There are vaccines available; however, birds given the live vaccine for ILT become lifelong carriers who can spread the disease to non-vaccinated birds.  Because of this, in some states the live vaccine is illegal.  There are also pox-vectored vaccines that contain part of the ILT virus but do not contain the entire live virus.  These are combination vaccines that also protect against Fowl Pox or Avian Encephalomyelitis.  Good biosecurity (sanitation measures and quarantine procedures) is just as important as vaccination for this disease and many others. Treatment often involves antibiotics to treat secondary infections and supportive care. In some cases your veterinarian may need to gently remove mucoid plugs using an eyedropper. 

SOURCES:

Infectious Laryngotracheitis | Michigan State University Extension(Non-Compassionate Source)

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

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Impacted Oviduct

Hens can develop an impacted oviduct for a variety of reasons including infection, inflammation, neoplasia, or a combination of these. Salpingitis, inflammation of the oviduct, is often an underlying cause of oviductal impaction. Whatever the underlying cause, the result is the inability of a follicle or egg to pass through a portion of the oviduct. This can often be a fatal condition if not addressed early on in the disease process. Depending on where in the oviduct the impaction occurs, the impacted material may simply be egg yolk (the material that surrounds a developing oocyte in a follicle), or may be a shelled egg. Despite this blockage, the hen’s ovary will continue to release follicles, which will add to the impacted material. In some instances, if the underlying cause resolves and there is only a small amount of impacted egg material, the hen may be able to pass the material on their own- this is generally referred to as an acute oviductal impaction. Oftentimes, however, this is not possible, and the impacted material is added to every time the hen’s ovary releases another follicle (upon surgical removal or necropsy, if the impacted material is cut open, you can often see the various layers of egg material that were added to over time). This is then classified as a chronic oviductal impaction which results in a serious, but slow growing problem, with each subsequent follicle adding another layer to the original impaction. This, compounded by the chicken’s naturally high body temperature of about 106-107 degrees Fahrenheit, results in the egg matter essentially cooking inside the chicken’s oviduct. If you see a drastic decrease in egg production in a resident who has not been implanted, you should closely monitor her for clinical signs of an oviductal impaction so that you can get her to the veterinarian before she is showing signs of a serious issue. Oviductal impaction can be confirmed via ultrasound, but can sometimes also be palpated during a physical examination depending on their size, which can range from very small up to soft ball size or larger. Hens with chronic impactions often have visibly distended bellies that may be completely firm or feel a bit fluidy, but do not have the same water balloon feel as the abdomen of a bird with reproductive tract cancer. Severe impactions can result in oviductal rupture which could then cause secondary egg yolk peritonitis. In some cases, salpingectomy (removal of the oviduct) may be recommended but is a risky and complicated surgery. If, for whatever reason, surgery is not recommended, the condition can sometimes be managed temporarily through the use of regular NSAIDs and a pulse antibiotic therapy (regular intervals of antibiotics interspersed with time off antibiotics) to keep infection at bay. This is not curative though and depending on the severity of the issue, may not provide the hen with a good quality of life. As the impaction grows, it will put pressure on the hen’s air sacs, which could result in cyanosis and open mouth breathing. Whether surgical intervention or medical management is pursued, the hen will also benefit from Suprelorin implantation, if possible. Always discuss treatment options with your veterinarian.

SOURCES:

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

Diseases of Poultry 13th Edition | David Swayne (Non-Compassionate Source)

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Internal Laying

Internal laying refers to the accumulation of egg follicles in the chicken’s abdominal cavity. This happens when follicles change direction and are discharged internally instead of exiting out of the oviduct and being laid. This could be caused by a number of conditions, such as inflammation, infection, or cancer (or following a salpingectomy if the ovary does not regress). Sometimes, internal yolk can be reabsorbed by a healthy hen, especially if it remains intact and does not rupture, but shell membranes, hardened egg masses, and ruptured follicles can quickly cause secondary problems, and repeated internal laying quickly compounds health risks including egg yolk peritonitis. In severe cases, surgery may be required to save the bird’s life, though this intervention can carry significant risk. You can potentially help a bird recovering from internal laying with implantation

SOURCE:

Internal Layer (Poultry) | Merck Veterinary Manual

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Lice

There are numerous types of lice that can affect chickens, but the most common is the Chicken Body Louse which is typically found around the vent or on the breast or thighs of a chicken. Chickens with lice might appear itchy and seem to scratch or shake their heads often. They may also have poor feather condition, and severe infestations can cause scabbing. Lice move quickly, so it can sometimes be difficult to find them if a chicken only has a few. Their bodies are translucent yellow and oblong.  There might also be white sugar-looking particles around the base of the feathers which are lice eggs.  Poultry lice is different from the head lice that affects humans and the types of lice that affects other mammals. While poultry lice can live on chicken host a few months, they can only survive for about a week off of their host. This means, while humans can have poultry lice on them (and this is quite common after handling a chicken with a lice infestation) the lice cannot survive on a human for long. Chicken body lice spread from bird to bird primarily through contact with affected birds.  Treatment options include ivermectin (in most cases injectable ivermectin can be given orally to chickens) and a topical treatment such as Frontline spray (be aware this is extra-label use) or a permethrin spray or powder. Be extremely cautious using topical treatments such as Frontline and follow your veterinarian’s recommendation or package instructions regarding how much to use to prevent an accidental overdose.

SOURCES:

Lice Of Poultry | Merck Veterinary Manual (Non-Compassionate Source)

External Mite And Insect Parasites Of Backyard Poultry | Entomology At The University Of Kentucky (Non-Compassionate Source)

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Marek’s Disease

Marek’s Disease is caused by a variant of a highly contagious herpes virus that infects the immune system of both chickens and turkeys. Chickens are the most important natural host for Marek’s Disease Virus (MDV). This virus causes neurological signs and tumors, typically in birds younger than 5 months old. MDV is considered one of the most ubiquitous avian infections worldwide; because of this, almost every flock is presumed to be infected. Most chickens raised in industrial settings are vaccinated against it, but the vaccine is only effective when the birds are very young, before they have had any exposure whatsoever to this herpes virus. Chicks are typically vaccinated when they are one-day old. The reasoning behind this practice is this: whichever virus the bird is exposed to first (be it the vaccine or the field virus), this is the one that takes control and the one that the bird will develop a lifelong immunity for.

Because of the prevalence of MDV, vaccinating an adult bird is generally not recommended and will not assist in fighting the virus. Unfortunately, some of the stronger strains of MDV can overcome the vaccine strain no matter the age of the bird when they were vaccinated- this is why some birds can still develop Marek’s disease despite being vaccinated at an early age. The vaccine does not prevent a bird from spreading MDV to other non-vaccinated birds; the vaccine will only reduce shedding and infections from the virus but does not completely eliminate it. One study found that the vaccine actually caused the disease to spread more quickly and can lead to significantly worse outbreaks of the “hot” (most harmful) strains. Some breeds, like Silkies and Sebrights, are very prone to catching it.

It is extremely contagious and is released into the environment from the feather follicles- the dust and dander from chickens serves as the primary method of the disease spreading. MDV can live in the environment for many months. Signs for concern are extremely variable, often making the disease hard to suspect by clinical signs alone. This is a reason why MDV is so commonly discussed as a possibility when a veterinarian examines a sick chicken. In some cases, individuals with Marek’s may just show signs of being depressed then pass away suddenly. The most common syndrome that can raise a red flag for MDV includes a progressive paralysis in one wing (resulting in a dropped wing) and paralysis in the leg, head tilting, and abnormal droppings. MDV later causes neck paralysis, irregular-sized pupils, blindness, and extreme weight loss. It ultimately results in enlarged nerves and in tumor formation in nerve, organ, muscle, and epithelial tissue.

Some chickens can suffer from progressive neurological issues, but if they are able to fight off the virus while you provide supportive care, they can recover and then will have a new immunity to that strain. There is no cure for Marek’s disease. Some recommend trying out a regimen of lysine (which inhibits herpes virus growth) or hypericum and supplementing with vitamins E and C. You can also talk to your veterinarian about the use of Gabapentin and other analgesics to manage any pain associated with Marek’s.

Although it can be hard to find symptoms of the disease in affected flocks, chickens with weakened immunity or new birds who enter a disease-carrying flock and are not vaccinated can exhibit symptoms of the disease. Affected chickens can be more susceptible to other diseases, but can potentially live for years with it. Only a necropsy can completely confirm Marek’s as the sole cause of death. A blood test or testing on the feather can be performed, however, these tests cannot differentiate between a vaccinated bird and an actively infected bird, so even if the results come back positive you cannot say with 100% accuracy that the bird is suffering from a MDV infection or if there is another cause of illness.

SOURCES:

Marek Disease in Poultry | Merck Manual (Non-Compassionate Source)

This Chicken Vaccine Makes Its Virus More Dangerous | PBS News Hour (Non-Compassionate Source)

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Mites

Chickens can be affected by a variety of mites, including the Northern Fowl Mite (Ornithonyssus sylviarum), the Poultry Red Mite (Dermanyssus gallinae), the Tropical Fowl Mite (Ornithonyssus bursa), and the Scaly Leg Mite (Knemidocoptes mutans). For information on the Scaly Leg Mite, please follow the link above. 

Northern Fowl Mite– This blood-sucking parasite affects numerous species of birds, including chickens and turkeys. Northern fowl mites live on the feathers of the host, laying their eggs at the base of the feather, and traveling to the host’s skin to feed. The vent area is the most common site for northern fowl mites, but they may also be found on the legs, around the preen gland, or on other areas of the body. Patches of mites create a dirty appearance, similar to that of feathers caked with feces or mud, but upon closer inspection, you will be able to detect movement of mites. Heavy infestation can cause considerable damage to the skin, such as crusting and scabbing, and can also cause anemia, which in severe cases can be life-threatening. Northern fowl mites can live off the host for weeks depending on the temperature and humidity. 

Poultry Red Mite (also known as Red Mite, Chicken Mite, Roost Mite, or Poultry Mite)– This blood-sucking mite affects numerous avian species, including chickens, turkeys, and pigeons. While red mites can bite other animals, including humans, they cannot survive on them. Red mites are nocturnal, feeding at night and spending the day off of their host in cracks and crevices in the living space, on roosts, or in nest boxes. Females lay eggs off the host, as well. Red mites are small, but visible to the naked eye. However, detection of red mites, especially at low levels, can be difficult since they are not on the host during the day. If you suspect red mites, you can check your residents at night, or you can thoroughly examine nest boxes, roosts, and other likely daytime hiding spots. Some sources suggest taping a piece of corrugated cardboard in the area where residents roost, as red mites will likely move to the cardboard during the day, making detection easier. Signs of a red mite infestation include general irritation/agitation and birds changing where they roost at night. Chickens may become anemic due to blood loss, and in cases of severe infestation, this anemia can be life-threatening. Red mites can live off the host for months.

Tropical Fowl Mite–  This mite affects various wild and domesticated bird species, including chickens, turkeys, and ducks, and if a bird host is not available, this mite will bite humans. Tropical fowl mites are similar to northern fowl mites, but lay eggs both on the host and in the bird’s nest. As the name suggests, this mite is found most often in warm regions.

Chickens become infected with the above mites through direct contact with infected birds (including wild birds), from other animals (including humans) who have come in contact with the mites, or from fomites or an infested environment. Proper quarantine procedures play an important role in preventing the introduction of mites to your residents and their living spaces, though wild birds can also be a source of infection. Eradication of mites can be difficult and should involve treatment of the individual birds as well as the environment (treatment of the environment is especially important when dealing with red mites). Your veterinarian can make treatment recommendations, which may include Ivermetin and/or Frontline (Fipronil) spray- some treatments may require off-label use. Be aware that some insecticide treatments are effective against mites but dangerous (both to birds and humans). Always use caution and be sure to follow your veterinarian’s instructions regarding application to avoid accidental overdose. While diatomaceous earth is often recommended as a safe and “natural” treatment, it is rarely enough to treat a mite infestation and is harmful if inhaled. There are various premise treatments that can be used to treat the habitat, but be sure to read all instructions and remove birds for as long as necessary based on package instructions (and do not return them to the space until all fumes have dissipated).

SOURCES:

Red Mites | The Chicken Vet

Mites Of Poultry | Merck Veterinary Manual (Non-Compassionate Source)

Chicken Mite | Veterinary Entomology (Non-Compassionate Source)

Northern Fowl Mite | Veterinary Entomology (Non-Compassionate Source)

Northern Fowl Mite | The Chicken Vet (Non-Compassionate Source)

Tropical Fowl Mite | University Of Florida (Non-Compassionate Source)

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

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Molting

Chickens naturally lose and replace their feathers through a process called molting.  This process typically happens annually in mature chickens and usually occurs in the late summer or early fall when the days begin to get shorter. Be aware that stress, illness, and other environmental factors can cause a chicken to molt, regardless of the time of year (as can the administration of a Suprelorin implant). The molting process can take weeks or months, and while molting does not make a chicken sick, it is an uncomfortable process and requires a lot of additional energy (which is why molting typically occurs when egg production drastically slows or stops for the season). New feathers are called pin feathers.  When they first come in, pin feathers resemble a porcupine quill. These new feathers can be very uncomfortable to chickens when they are coming in. Pin feathers also have a blood supply and will bleed if they are broken (pin feathers are sometimes called “blood feathers”). A broken pin feather can bleed quite a bit and should be addressed immediately. In addition to being an uncomfortable process, the creation of new feathers uses a lot of energy. Feathers are comprised mostly of protein, so feeding protein-rich treats or temporarily switching molting chickens to a higher protein food may be beneficial. It is not uncommon for a molting chicken to be a bit less active or eat a bit less than normal, but if they are acting sick or not eating at all, there could be something else going on, and they should be seen by a veterinarian.  Also keep in mind that not all feather loss is caused by molting- external parasites, bullying, obsessive preening, and being mounted by roosters can also cause feather loss.

SOURCE:

When And Why Do Poultry Molt? | Backyard Poultry (Non-Compassionate Source)

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Mycoplasma 

The term Mycoplasmosis is used to refer to infectious diseases caused by micro-organisms called Mycoplasma. Chickens can be affected by numerous mycoplasmas, but one of the most common is Mycoplasma gallisepticum which can cause chronic respiratory disease in chickens, as well as other birds such as turkeys and gamebirds. This condition is spread from bird to bird through respiratory secretions and aerosols and can also be spread by contaminated clothing, equipment, or other fomites. Clinical signs can range from very mild to severe respiratory distress. You may note nasal discharge and bubbles around the eyes in addition to swelling around the eye. Birds affected by mycoplasma can become vulnerable to secondary viral or bacterial infections. Your veterinarian can perform laboratory testing for an official diagnosis. Thankfully, successful resolution frequently occurs with early identification and proper antibiotic treatment. Your veterinarian may recommend a flock-wide treatment in addition to treating symptomatic residents individually. More advanced cases sometimes require surgical debridement of the sinuses in addition to antibiotic treatment. Birds infected with Mycoplasma gallisepticum often have future episodes of illness, especially during times of stress or sudden temperature fluctuation.

SOURCES:

Session 3: Respiratory, Neurological And Musculo-Skeletal Diseases | Backyard Poultry Online ‘Mini Series’

Mycoplasma gallisepticum Infection in Poultry | Merck Manual (Non-Compassionate Source)

Mycoplasmosis | Poultry Hub (Non-Compassionate Source)

Mycoplasma: How to Deal with a Persistent and Ubiquitous Pathogen  (Non-Compassionate Source)

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Newcastle Disease

This is a highly contagious viral disease that is a worldwide problem and primarily presents as an acute respiratory disease. Severity of disease is based on many factors including the virulence of the virus. The World Organisation For Animal Health (OIE) describes three forms of the disease: lentogenic (or mild), mesogenic (or moderate), and velogenic (or very virulent). Lentogenic strains, while widespread, cause few disease outbreaks, according to the OIE, and are not reportable. Virulent Newcastle disease (vND, sometimes referred to as Exotic Newcastle disease) is a reportable disease. Infected birds will shed the virus in their respiratory discharges and feces. It can also be present in eggs that are laid by infected birds. Birds may become infected through direct contact with infected birds or by coming into contact with food, water, equipment, or other fomites contaminated with the virus. Clinical signs typically appear 2-12 days after exposure, with the average being 5 days following exposure. There are different forms of this disease which affect different areas of the bird’s body. Respiratory signs can include coughing, sneezing, gasping for air, and audible and abnormal breathing sounds. Very young birds as well as older birds with a weakened immune system are the most severely affected. Nervous signs may include depression, paralysis, tremors, and circling. In females who are actively laying, they may lay abnormal eggs, lay fewer eggs, or stop laying all together. Typical signs of vND include respiratory illness, watery green diarrhea, depression, and swelling of the tissues of the head and neck.

In addition to the concern regarding how vND would affect your residents if they became infected, is the concern regarding how your residents could be affected by regional efforts to eradicate the disease. During a recent outbreak of vND in California (2018-2020), immediate efforts to contain the disease included quarantining affected areas and compulsory mass killings of birds regardless of whether or not they had actually been infected. After push back from the community, some exemptions were granted for birds who were not showing symptoms of disease so long as their human companion kept them indoors where they could not come into contact with other birds, agreed to regular vND testing, and agreed not to move them out of the area. These exemptions were made on a case-by-case basis, but the important point is that they became available because people advocated for birds who had not been infected to be spared. When faced with a decision that you are uncomfortable with, always reach out to other veterinarians or sanctuaries to figure out if there are other options that may be available, and always advocate for your residents. We recommend you pay attention to vND outbreaks and have a plan in place to protect your residents should it be detected in your area. Vaccines are available for this disease, but are not typically recommended in a sanctuary and are not guaranteed to prevent infection.

SOURCES:

Newcastle Disease | World Organisation For Animal Health (Non-Compassionate Source)

Newcastle Disease in Poultry | Merck Veterinary Manual (Non-Compassionate Source)

Virulent Newcastle Disease (vND) | USDA APHIS (Non-Compassionate Source)

Diseases of Poultry 13th Edition | David Swayne (Non-Compassionate Source)

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Osteomyelitis

Osteomyelitis, infection of the bone, can be caused by various pathogens, but Staphylococcus aureus and Escherichia coli are often to blame. Osteomyelitis can occur following a compound (or open) fracture, an advanced case of bumblefoot, or a chronic keel sore. Chickens may develop a keel sore as a result of lying down more than usual due to illness or injury, and/ or due to obesity (particularly in large breed chickens) or lying down on hard, abrasive surfaces. Prognosis of osteomyelitis depends on which bone(s) and how much of the bone is infected. Treatment may include antibiotic-impregnated beads or regional limb perfusion, depending on the location of infection. Surgical debridement of infected bone may be possible, but if the entire bone is affected, prognosis is poor. In the case of osteomyelitis following a compound wing fracture, wing amputation may be necessary.

SOURCES:

Top Ten Orthopedic Diseases- Avian | VetFolio

Infectious Skeletal Disorders in Poultry | Merck Veterinary Manual (Non-Compassionate Source)

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Prolapsed Vent

If you see tissue protruding from a chicken’s vent, this is a prolapse. Severity depends on the amount of tissue that has prolapsed, whether the tissue is damaged or necrotic, whether or not the tissue can easily be reinserted, and how the chicken is behaving overall. Be aware that other chickens will likely peck at another bird’s prolapsed tissue (especially if there is any sign of blood in the area), causing damage, so a chicken with a prolapsed vent should be kept away from other birds. When moving a chicken with a prolapsed vent, it’s safest to do so using a carrier, especially for bigger chickens. Sometimes the stress of handling causes the bird to further strain and prolapse more tissue. If carrying a smaller chicken, keeping one hand firmly behind their vent to prevent further prolapsing can be helpful.

A very small prolapse of healthy looking tissue may go in on its own with little intervention. You can try gently blowing on the tissue, and if that doesn’t work you can use a sterile glove and lubricant and try to gently reinsert the tissue. If the tissue does not go in easily and stay in, the chicken should be moved to a safe space away from other birds.

Work with your veterinarian to have the chicken assessed, both to have the prolapse itself addressed and also to determine the underlying cause of the prolapse. In addition to ensuring birds are not able to peck at the exposed tissue, the other important thing is to keep the tissue from drying out. This can be done by applying a lubricant, such as KY Jelly, to the exposed tissue multiple times during the day. Your veterinarian will likely recommend an anti-inflammatory medication and an antibiotic. If the chicken does not have a Suprelorin implant, you should discuss this option with your veterinarian.

SOURCE:

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

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Reproductive Tract Cancer (Ovarian or Oviductal)

Reproductive tract cancer is the most common source of tumors of unknown origin in hens. It’s often the result of excessive egg-laying through generations of selective breeding and typically affects hens when they are about 2 years old (which is typically the age at which they are considered “spent”). Breeds typically used in industrial settings are commonly affected because they have been bred to lay such a large number of eggs. Anecdotally, Leghorns seem to be especially prone to developing reproductive tract cancer. Because it is more common in breeds used in industrial settings, and because it often develops at the time these hens are no longer considered profitable, many veterinarians may not have the opportunity to see this condition first hand.  Ultrasonography, and a more detailed CT scan, can be used to confirm a suspected reproductive tract cancer diagnosis, but not all veterinarians have experience imaging a chicken’s reproductive tract. These cancers often present as large amounts of accumulated abdominal fluid- much more than is typically produced from Egg Yolk Peritonitis. This fluid carries cancer cells to other areas of the abdomen and throughout the body via the bloodstream. As it spreads, the intestines often become affected and become thickened and firm. This thickening can result in emaciation and secondary crop issues because food has difficulty passing through the intestines. Fluid can be removed from the abdomen using a needle and syringe, but this practice must be taught to you by a veterinarian or highly experienced care expert. Improper technique could result in infection or damage to internal organs or air sacs. In some cases, it may be better to have the bird sedated during this procedure. Your veterinarian can also explain to you when you should remove the fluid, as removal actually encourages the creation of more fluid, so removing fluid too frequently can worsen the condition. However, fluid build-up can also put pressure on air sacs and can cause birds to be very uncomfortable, so fluid removal must be done thoughtfully. Cancerous fluid removed from a chicken’s abdomen is often translucent rather than opaque (either a translucent yellow or completely clear). Reproductive tract cancer produces such large amounts of fluid build-up that it could be possible to remove up to a liter of fluid from a chicken’s abdomen at one time. This fluid is typically sterile, so antibiotic use is not typically advised. Chickens with large amounts of fluid in their abdomen will often have visibly distended abdomens, and their abdomen will feel fluid-filled and tight, much like a water balloon. There is no cure for reproductive tract cancer, though there are drugs that your veterinarian can recommend, such as Tamoxifen, that can manage the disease for a time. A chicken suffering from reproductive tract cancer could potentially be given a Suprelorin implant to remove the extra stress of egg production. In addition, it has been found that supplementing flaxseed can help alleviate Ovarian Cancer severity and incidence in chickens.

SOURCES:

Ovarian Tumors Of The Hen (Non-Compassionate Source)

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

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Reticuloendotheliosis

Reticuloendotheliosis is a group of diseases in several avian species causes by Reticulodotheliosis virus (REV). This virus causes neoplastic disease. It affects many more species of birds than MDV and ALV and can occur naturally in other birds at your sanctuary. However, it is not as prevalent as the other two viruses, and large clinical outbreaks are not commonly seen. Horizontal transmission is the most common way this virus spreads and occurs via feces and blood-sucking insects. “Runting syndrome” is generally the most common clinical sign which is seen in young chicks who have been infected. This can produce weight loss, anorexia, paleness, abnormal feathering, and occasionally lameness or paralysis. There is no treatment or vaccination for this virus and diagnosis, even at necropsy, is difficult.

SOURCES:

Reticuloendotheliosis in Poultry | Merck Manual(Non-Compassionate Source)

Diseases of Poultry 13th Edition | David Swayne (Non-Compassionate Source)

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Salpingitis

Salpingitis, or inflammation of the oviduct, is one of the most common reproductive tract diseases in chickens and is often an emergency issue. Salpingitis can have an infectious or non-infectious cause. Bacterial or viral infections can result in salpingitis- common infectious causes include E. coli, Streptococcus sp., Mycoplasma gallisepticum, Acinetobacter sp., Corynebacterium sp., Salmonella sp., and Pasterella multocia. Non-infectious causes include trauma, such as from passing a large egg or damage to prolapsed tissue. A common sign of salpingitis is the passing of “lash eggs,” which are not really eggs but are rather caseous material (cheese-like pus). Lash eggs can be various sizes and shapes and are typically firm and rubbery with a distinct smell. When cut open they may have liquid pockets and will also have various layers. While there are many online sources that say there is no treatment and the hen has no hope of survival, this is not true. A veterinarian can evaluate the hen to determine both the cause and the severity and will typically perform an ultrasound. It is important to try to establish a relationship with a veterinarian who has access to an ultrasound machine as this is a key diagnostic tool when dealing with salpingitis. Local veterinary universities may suggest performing a full CT on the chicken if she is stable enough for anesthesia in order to get the most answers as to what exactly is the cause and to determine the best treatment approach. Treatment typically consists of antibiotics, anti-inflammatory drugs, and potentially a Suprelorin implant. If medical management is not successful, your veterinarian may recommend surgical removal of the oviduct (salpingectomy), though this is a complicated and risky surgery.

SOURCES:

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

Salpingitis | The Poultry Site (Non-Compassionate Source)

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Scaly Leg Mites (Knemidocoptes Mutans)

Scaly Leg Mites, or Knemidocoptes mutans (sometimes spelled Cnemidocoptes mutans), is caused by a microscopic mite that burrows between the scales on a chicken’s legs. A telltale sign of scaly leg mites is raised scales on the legs and feet. While raised scales can be the result of an old infestation or other issue, it’s a good idea to treat chickens with raised scales as if they have scaly leg mites just to be safe unless you know that raised scales is normal for a particular individual.  Other signs are crusty scales, missing scales, and thickened skin in the area. Scaly leg mites are spread through contact with an affected bird. Covering a chicken’s feet and legs in petroleum jelly will suffocate scaly leg mites.  Depending on the severity and damage done to the legs, soaking and gently removing dead scales and tissue from the feet and legs first may be advised.  This treatment should be demonstrated to you by a veterinarian or expert before attempting to take it on yourself. Your veterinarian may also recommend administration of ivermectin, moxidectin, or a 10% Sulphur solution.

SOURCES:

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

Mites Of Poultry | Merck Veterinary Manual (Non-Compassionate Source)

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Soft-Shelled Eggs

Chickens who are actively laying eggs need a balanced diet to meet the demands of egg production. Poor nutrition can cause soft-shelled and malformed eggs, which can cause cloacal prolapse and egg-binding. Egg production demands a lot of calcium, and breeds used in industrial egg production can easily become deficient in calcium. The eggshell is developed last, and consists mostly of calcium carbonate, absorbed through diet and taken from their bones, so appropriate amounts of calcium are essential to a chicken’s health, especially if they overproduce eggs. If you feed the chicken’s eggs and shells back to them, they can replenish some of the lost calcium (you can read more about what to keep in mind when considering whether or not to feed a resident’s eggs back to them, here). You could also consider implanting a chicken laying soft-shelled eggs to potentially give their body time to recover. Be aware that soft-shelled eggs could also be a result of an issue in the oviduct.

SOURCE:

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

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Sour Crop (Candidiasis)

Sour crop is a yeast infection caused by an overgrowth of Candida, often Candida albicans, which is commonly present in the GI tract of healthy birds. There are a variety of factors that can cause an overgrowth of Candida- these include certain medications such as antibiotics or steroids, unsanitary drinking water, diets high in sugar or carbohydrates, and even excess stress. Sour crop can also be secondary to food fermenting in the crop due to a crop impaction or other disease processes that cause crop stasis. A chicken with sour crop will have a fluid-filled crop that is slow to empty. You may also notice a sour smell on their breath. Treatment typically includes the use of an antifungal treatment, such as Nystatin, and/ or an apple cider vinegar water treatment. Remember- never use a galvanized metal waterer to administer apple cider vinegar water, as the acid can damage the metal and contaminate the water. It’s important to also identify if the sour crop is secondary to another issue so that the underlying cause can be addressed as well. If intubation is recommended to remove the liquid or administer medication, you must be trained by an expert before attempting this technique.

SOURCES:

Candida Infections in Birds | Niles Animal Hospital And Bird Medical Center

Overview of Candidiasis in Poultry | Merck Veterinary Manual

Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners (Non-Compassionate Source)

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Wing Fracture

While a wing fracture can occur in any breed of chicken, they tend to be more common in newly rescued large breed chickens. In many cases, these fractures are the result of being handled roughly or restrained improperly. It is not uncommon for large breed chickens to sustain fractures to the wing during the process of being loaded into crates and transport vehicles to be sent to slaughterhouses or live markets. Individuals rescued from Kaporos ceremonies are also more likely to arrive with a fractured wing. In some cases, individuals will arrive with compound (or open) fractures- this means that some of the bone is exposed. It is imperative that individuals with compound fractures receive urgent veterinary care. Keeping the exposed bone and secondary wound covered with moist (but not wet) sterile gauze and the wing immobilized with a bandage will help prevent the bone from drying out and prevent further damage to the bone, skin, muscles and tendons. Compound wing fractures that become infected or necrotic often require wing amputation. While some veterinarians may express reluctance about performing a wing amputation, especially due to concern about the infection spreading to the air sacs and lungs (because of connection between the respiratory and skeletal systems), larger sanctuaries, as well as activists who regularly rescue Cornish crosses from Kaparos ceremonies have seen many individuals go on to live happy and mostly normal lives following a wing amputation (or even a double wing amputation), though these individuals may have balance issues, and without their wing(s) they may be more sensitive to the cold.

SOURCE:

Chicken Care | Farm Sanctuary

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Worms

There are many different parasitic worms that can affect chickens, so it’s important to talk to your veterinarian about common worms in your area and to work with them to establish preventative strategies, as well as fecal testing and deworming protocols for your sanctuary. Worms that can affect chickens include large roundworms, or ascarids, (Ascaridia galli); threadworms (Capillaria spp.); cecal worms (Heterakis gallinarum, which can carry Histomonas meleagridis, the causative agent of blackhead, a serious disease that turkeys are particularly susceptible to); gapeworms (Syngamus trachea); and multiple species of tapeworms. (Chickens can also be affected by parasitic protozoa such as Eimeria spp. which causes coccidiosis.) While low levels of parasitic worms may not cause an issue, higher levels can cause weight loss, depression, and other symptoms depending on the specific worm species. Parasitic infection can also make residents vulnerable to other diseases. Without treatment, severe infestations can be fatal. By performing routine fecal testing, you will get an idea of what parasitic worms, if any, your residents are harboring even if they are not showing clinical signs. Additionally, be sure to test individuals who are showing potential signs of internal parasites. Depending on the results and the individual’s clinical signs, your veterinarian can recommend treatment. The overuse of deworming medications (anthelmintics) can result in parasitic worms that are resistant to some or all medications. Best practice is to work with your veterinarian to determine when deworming is necessary and then to follow-up to ensure the treatment worked by comparing post-deworming fecal egg counts to pre-deworming counts. 

SOURCES:

Internal Parasites Of Poultry | Poultry Extension

Deworming Backyard Poultry | Penn State Extension

Internal Parasites | University of New Hampshire Cooperative Extension (Non-Compassionate Source)

Diseases of Poultry 13th Edition | David Swayne (Non-Compassionate Source)

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Non-Compassionate Source?

If a source includes the (Non-Compassionate Source) tag, it means that we do not endorse that particular source’s views about animals, even if some of their insights are valuable from a care perspective. See a more detailed explanation here.

Updated on May 4, 2022

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