What it looks like
Pale or whitish comb and wattles — Comb appears pale instead of bright red; indicates anemia and poor circulation
Poor feathering or feather loss — Feathers appear thin, dull, or patchy; birds may have areas of bare skin
Ruffled feathers and lethargy — Feathers look unkempt; birds appear depressed, inactive, or slow to respond
Poor growth and stunting — Young birds fail to grow at normal rate; appear undersized and weak
Bleeding and bruising — Subcutaneous hemorrhages (bruising under skin); may see blood-tinged droppings
Swollen head and face — Head appears puffy or edematous; may indicate severe infection
Death in severe cases — Sudden death without preceding illness; indicates acute infection or secondary complications
Likely causes
- Infection with chicken anemia virus (CAV), a small DNA virus that attacks bone marrow
- Vertical transmission from infected hens to eggs (congenital infection)
- Horizontal transmission between birds through respiratory droplets and fecal matter
- Stress (transport, overcrowding, vaccination) triggering clinical disease in infected birds
- Young birds and immunocompromised flocks most severely affected
What to do
No specific antiviral treatment for CAV. Focus on supportive care: provide clean water, nutritious feed, warmth, and low-stress environment. Vitamin supplementation (especially B vitamins) may help. Isolate infected birds to prevent spread. Euthanasia may be considered for severely affected individuals to prevent suffering and reduce 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 birds from CAV-negative flocks when possible. Practice strict biosecurity: separate by age groups, isolate new birds for 2-3 weeks, disinfect equipment between groups. Manage stress through proper housing, nutrition, and vaccination schedules. Test breeding flocks for CAV status if possible. Avoid bringing CAV-positive birds into negative flocks.
Frequently asked questions
What is chicken anemia virus?
CAV is a small DNA virus that attacks bone marrow, reducing red blood cell production and causing anemia. It can be congenitally transmitted (through eggs) or spread between birds horizontally. Stressed birds are more likely to show clinical signs.
Is CAV contagious between chickens?
Yes, CAV spreads through respiratory droplets, fecal-oral route, and contaminated equipment. Young birds are especially vulnerable. Recovered birds often become lifelong carriers and shed virus periodically.
Can I treat CAV?
No specific antiviral treatment exists. Management relies on supportive care, isolation, biosecurity, and stress reduction. Your vet may recommend vitamin supplementation or euthanasia for severely affected birds to prevent suffering.
Will my flock recover from CAV?
Some birds recover and develop immunity, but many die or remain chronically affected. Recovered birds often become carriers. Good management and biosecurity prevent new infections in the recovered group.
How do I prevent CAV in my flock?
Source birds from CAV-negative flocks. Quarantine new birds for 2-3 weeks. Maintain strict biosecurity (separate age groups, disinfect equipment). Minimize stress through proper housing and management. Test breeding flocks if possible.