Signs of disease usually appear in several or all birds in a flock, including:
- sudden death
- lethargy or reluctance to walk, eat or drink
- droopy appearance or ruffled feathers
- head or limb swelling
- bruising of the wattle, comb, feet or skin
- respiratory signs such as panting, nasal discharge or sneezing
- diarrhoea
- unusual head or neck posture, incoordination, inability to walk or stand
- unusual reduction in egg production.