Cyanosis of the head observed in cases of H5N7 highly pathogenic avian influenza strain

Subcutaneous hemorrhage characteristic of H5N7 strain of highly pathogenic avian influenza

Vesicle formation on the wattle of a bird infected with highly pathogenic avian influenza

Purulent conjunctivitis due to avitaminosis A

Incoordination and lateral recumbency in chicks may be due to avian encephalomyelitis, avitaminosis A, nutritional encephalomalacia or arenavirus infection

Severe pulmonary aspergillosis showing numerous nodular foci and confluent lesions

Characteristic 'hock sitting' posture of broiler with Mycoplasma synoviae arthritis

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