Characteristic posture of a chicken with Marek's disease showing extension of one leg and retraction of the other

Unilateral enlargement of nerve of the sciatic plexus is characteristic of Marek's disease

Keratitis and conjunctivitis following exposure to high levels of atmospheric ammonia

Accumulation of purulent material in the infraorbital sinus is characteristic of coryza

Ocular discharge and swelling of nasal sinus associated with coryza. Differential diagnosis includes mycoplasmosis or laryngotracheitis

Acute onset of ocular discharge accompanied by high flock morbidity may denote infectious larngotracheitis, infectious bronchitis, coryza or mild avian influenza

'Swollen Head Syndrome' in broiler showing cellulitis of the face and head with symblepharon (closed eyes)

Broiler with swollen face and dyspnea due to laryngotracheitis