1. Home
  2. Knowledge Base
  3. Animal Guides
  4. Chickens
  5. Fatty Liver Hemorrhagic Syndrome In Chickens: Symptoms, Cause, And Prevention

Fatty Liver Hemorrhagic Syndrome In Chickens: Symptoms, Cause, And Prevention

A black hen walks on a grassy field.

Updated 4/30/2021

We have updated this resource to focus on fatty liver hemorrhagic syndrome in chickens. We are currently working on gathering information to provide species-specific information about hepatic lipidosis in turkeys, ducks, and geese.

What Is Fatty Liver Hemorrhagic Syndrome?

Fatty Liver Hemorrhagic Syndrome (FLHS) is an unfortunately very common non-infectious disease that causes fatalities in chickens with few outward symptoms in the time leading up to their unexpected death. Although it is most associated with hens who are used in egg production (especially those confined to cages), it has also been known to affect chickens in non-commercial settings. Because estrogen plays a large role in the disease, FLHS is unusual in male birds. The disease is very similar to the human ailment known as nonalcoholic fatty liver disease.

The disease causes an afflicted bird’s liver to gradually accumulate fat, killing their liver cells and replacing the functioning liver with scar tissue. Their liver grows and becomes more fragile to a point where it either can no longer properly function, or the liver ruptures, and the bird dies as a result of internal bleeding. Sometimes the rupture is associated with the stress of laying an egg with an enlarged liver.

The disease is most likely to cause death in the summertime months, possibly due to the added stress of heat and reduced inclination to exercise.

What Causes FLHS?

Due to the way that birds remove lipids from their liver (by using a form of protein), those who have a protein or specific amino acid deficiency end up accumulating excess lipids in their liver.

It has been found that FLHS is caused by a number of possible concurrent variables, including the following:

  • A genetic predisposition to the disease
  • Stress from heat, especially in the summertime
  • Reduced exercise and obesity
  • Egg-laying (increased estrogen from laying leads to higher rates of the disease)
  • Excessive high carbohydrate foods (such as scratch or corn)
  • Excessive high fat foods (such as black oil sunflower seeds)
  • Generally, a low-protein high-fat diet (protein less than 17.5% and fat greater than 3.5%)
  • A Biotin, Choline Chloride, Copper, or Vitamin E deficiency
  • Tainted or moldy food
  • Increased age increases the risk of the disease
  • Metabolic disease (such as a thyroid dysfunction) is associated with increased risk
  • Both Mycoplasma Gallinarum infections and vaccinations are associated with increased risk

What Are The Symptoms Of FLHS?

Although it is quite difficult to discern that a bird is suffering from FLHS, there are some indicators of the disease, including:

  • Obesity
  • A pale comb (in a non-implanted hen; implanted hens have pale combs)
  • Comb dandruff
  • Greenish diarrhea or yellow droppings
  • A quick drop in egg-laying in a non-implanted hen
  • Lethargy or a refusal to move as much as they used to
  • Difficulty breathing
  • An enlarged or distended abdomen
  • Excess fat in the bird’s abdomen
  • A more “fluffed up” appearance than usual
  • Brittle eggshells due to worsened calcium metabolism

How Can FLHS Likelihood Be Reduced?

Generally, the best prevention for FLHS comes with adjustments to diet, exercise, living spaces, and reproductive care, including:

  • Providing heat relief in the summertime
  • Increased exercise and incentivized movement
  • Food restriction as necessary to control a bird’s weight
  • A high protein, low fat diet
  • A lower carbohydrate diet (such as wheat or barley)
  • 6% oat hull supplementation in their diet
  • Adding organic selenium, ethoxyquin, Vitamin E, Vitamin B12, Choline chloride, and Inositol (cantaloupe is a good source) into a bird’s diet
  • Providing fewer high calorie or high fat treats
  • Providing fresh fruits and vegetables in a bird’s diet
  • Supplementation of dandelion, alfalfa meal, and milk thistle may be able to help an FLHS-afflicted bird
  • Implanting egg-laying chickens, potentially

If You Suspect A Chicken Has FLHS

If you are at all concerned that a bird under your care may be developing FLHS or is at all under the weather, it’s important to contact a veterinarian as soon as possible. Never assume a bird will get better if something seems amiss. Birds hide illness as a defense mechanism, and once they become symptomatic, their ailments tend to be in advanced stages. Speaking up can save a life.

If you have to wait for a scheduled veterinary consultation, quarantine them and give them a cooler space with easy access to some food and water.


Overview of Fatty Liver Hemorrhagic Syndrome in Poultry | The Merck Veterinary Manual

Fatty Liver Haemorrhagic Syndrome | Diseases Of Poultry (Non-Compassionate Source)

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

Low Protein And High-Energy Diet… | Oxford Academic (Non-Compassionate Source)

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 March 17, 2022

Related Articles

Support Our Work
Please consider supporting The Open Sanctuary Project by making a donation today! We are 100% donor-funded and rely on the support of generous individuals to provide compassionate resources to animal caretakers worldwide.
Donate Now HERE