What it looks like
Pale or enlarged abdomen — Belly appears swollen or distended; bird sits unusually upright or awkwardly
Lethargy and depression — Bird is inactive, sits with fluffed feathers, unresponsive to environment; appears chronically ill
Poor growth or stunting — Affected birds fail to gain weight or feather out normally; smaller and weaker than flockmates
Pale comb and wattles — Comb and wattles lack normal bright red color; appear pale or anemic
Ruffled or unkempt feathers — Feathers appear fluffed, matted, or poorly groomed; bird neglects feather maintenance
Lameness or leg paralysis — Bird drags legs or becomes unable to stand; paralysis may develop in hind legs (ALV-induced tumors affect nerves)
Reduced or ceased egg laying — Laying hens stop producing eggs or production drops dramatically
Likely causes
What to do
No cure for avian leukosis. Treatment is supportive and palliative: provide comfortable housing, good nutrition, and clean water. Reduce stress and handle minimally. Some birds may survive for months or years with chronic signs; others decline rapidly. Euthanasia is often recommended for severely affected birds to prevent suffering and reduce flock transmission.
When to see a vet
See a vet if your bird shows severe signs or doesn’t improve within a few days of treatment.
Prevention
Source chicks from hatcheries with ALV-tested, disease-free breeder flocks. Maintain strict biosecurity: isolate new birds for 2-3 weeks before mixing. Avoid purchasing birds from mixed or unknown sources. Test breeding flocks regularly if you raise your own replacements. Practice good sanitation and prevent wild bird contact. Avoid poultry shows or cross-flock contact if possible.
FAQ
Is avian leukosis contagious?
Yes. ALV spreads through contact with infected birds’ bodily fluids, feces, and respiratory secretions. It can also be passed from hens to chicks before hatching. Isolate any identified or suspected birds. Clean and disinfect equipment and housing thoroughly.
Can infected birds spread ALV to humans?
No. Avian leukosis is not zoonotic and does not infect humans. You can safely handle infected birds using standard hygiene practices. However, maintain biosecurity to prevent spread to other birds in your flock or neighboring flocks.
How do I know if my bird has avian leukosis or just poor health?
ALV causes gradual decline: chronic lethargy, poor growth, pale comb, and sometimes lameness or tumors. Many illnesses cause similar signs. Your vet can perform blood tests or necropsy to confirm ALV. Other conditions (parasites, poor nutrition) must be ruled out.
What should I do if I find a tumor on my bird?
Isolate the bird and contact your vet for examination and testing to confirm the cause. With an undiagnosed tumor, do not consume eggs or meat from the bird until the cause is known — tumors can come from ALV or other diseases, and testing determines which.
Can I eat eggs or meat from birds with avian leukosis?
With confirmed avian leukosis (not another disease), eggs and meat are safe to eat after proper cooking, since ALV does not infect humans. However, infected birds often taste poor and have reduced productivity. Most keepers cull infected birds to prevent flock spread. If a tumor is found on an undiagnosed bird, do not consume it until your vet confirms the cause.
For more help, try our chicken symptom checker or read about signs your chicken is sick.