All about Lymphoid Leukosis (Avian Leukosis) disease

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All about Lymphoid Leukosis (Avian Leukosis) disease|caLymphoid Leukosis is a tragic disease that affects a chicken's liver and can cause a painful death. Because of that, humane euthanasia is usually recommended to ease the suffering of poor birds that contract this illness and to help prevent the spread of the disease to other members of the flock. You'll definitely want to consult with a veterinarian if you suspect a member of your flock has this disease. Read on to find out more:

Lymphoid Leucosis Also called
Liver cancer, Liver disease, LL


General signs -
Fatigue, weakness, ruffled feathers, depression, lethargy, loss of appetite, drop in laying, shriveled comb, loose poo, death

Cardinal or diagnostic signs -
Post mortem signs may be diagnostic: tumors in liver or other organs, swollen joints


Yes -- spreads through contact, droppings, blood (for example: mosquitoes), or from hen to chick through the egg. Late-feathering birds are thought to be more susceptible to the virus.

Communicability to humans

Incubation period
14 weeks, onset usually occurs around laying age.

Yes, especially if the virus was passed in ovo from its mother.


Home treatment and/or prevention
Prevention: Practice good biosecurity. Unfortunately, this disease is difficult to prevent, even with good management practices. Purchase poultry from reputable, NPIP (National Poultry Improvement Plan) sources that closely monitor their flocks' health.

Treatment: None. This usually leads to a painful death, although some birds can survive to be carriers and infect others. Consult your vet to be sure, but generally, this is one of those tragic illnesses where it's advisable to humanely euthanize affected birds so they don't infect others. Sanitize the coop and run, and be sure to also sanitize the brooder and/or incubator.

Veterinary care
None. Your vet can humanely euthanize suffering birds, and may have good advice for sanitizing the coop/run/brooder.

No, however some birds can survive to shed the virus.

Other conditions, illnesses and/or diseases with similar signs:
Marek's disease, pullorum.

Also consider browsing through this list of other chicken illnesses with neurological symptoms.