The common signs & symptoms include -
Coughing
Sneezing
Rales / snoring
Discharges from eyes and nostrils
Gasping
Swelling of the face and/or wattles
Bluish-purple discoloration of the face
Diarrhoea - mostly greenish
Poor appetite
Lack of energy
Red or white spots on the legs and comb
Conjunctivitis
Drop in egg production
Production of soft or mis-shapen eggs
Sudden deaths in flock without any warning signs
Post-mortem Signs:
Congested Muscles
Subcutaneous oedema of head and neck
Necrosis of skin of comb and wattles
Inflammation of sinuses, trachea, air-sacs & conjunctiva
Ovarian regression or haemorrhage
Haemorrhage in proventricular & gizzard mucosae, and lymphoid tissue of intestine