Newcastle disease in chickens: signs and prevention

27 September 2026 · ZARI AGRI

Newcastle disease is a contagious viral disease of birds. A sudden rise in deaths, breathing problems, a drop in egg production, or nervous signs can raise concern, but these signs also occur with other poultry diseases. Laboratory confirmation matters.

What should you watch for?

Look for a sudden change in appetite or activity, coughing or difficult breathing, diarrhoea, a sharp fall in laying, twisting of the neck, poor coordination, or unusual deaths. Signs differ with the virus strain, age and immunity of the birds. Do not assume that one symptom proves Newcastle disease.

What to do when disease is suspected

Limit movement of birds, people and equipment between the affected flock and other flocks. Keep new birds separate, clean and disinfect shared equipment, and contact a veterinarian or the local animal-health service promptly for testing and local reporting instructions. Avoid selling or moving sick birds while the cause is being investigated.

How to reduce future risk

Use a vaccination programme designed by a local veterinarian for the flock and area. Control visitors, source birds carefully, maintain clean housing and drinking water, and separate birds of different health status where feasible. Vaccination and biosecurity work together; the schedule and vaccine handling must follow local professional guidance.

Record the outbreak

1. When signs began, flock size, bird ages and recent introductions.
2. Daily deaths, egg production and the number of birds with symptoms.
3. Vaccination history and recent movements of birds or equipment.

This article cannot diagnose a flock. Sudden deaths or rapidly spreading illness require urgent local veterinary advice. Do not start a medicine or vaccine as treatment based only on this page.