Abstract
Background:
Early chick mortality is one of the most important problems of poultry industry that cause severe economic losses to the farmers. The chick mortality varies in different geographical locations and its etiological factor also varies.

Aim:
Present work was aimed to isolate and identify various etiological agents responsible for causing early chick mortality in broilers, study the overall occurrence and pathology of various disease conditions responsible for causing early chick mortality in broilers.

Methods:
The study included clinical and laboratory investigations vis-a-vis early chick mortality. A total of 2346 broiler chickens under the age group of two weeks from around 87 outbreaks were necropsied and examined for presence of lesions corresponding to different disease conditions. Representative samples (heart, liver, Intestine, lung and spleen) were collected in a sterile Petri dish for bacterial and fungal isolation and stored at 4ºC till inoculation in nutrient broth, followed by collection of tissue samples (heart, liver, lung, spleen, intestines and kidney) in 10% buffered formalin for histopathological examination.

Results:
The overall mortality in the flocks was 1.7%, with 1.6% mortality in the first week and 1.8% in the second week of life. Colibacillosis was responsible for causing highest early chick mortality of 2.01% followed by salmonellosis (1.9%), aspergillosis (0.9%) and gout (0.6%). The case prevalence of colibacillosis, salmonellosis, aspergillosis and gout was seen as 58.1%, 32.3%, 6.4% and 3.2% respectively. Colibacillosis (2.1%), salmonellosis (3.2%) and gout (1.7%) were responsible for causing higher mortality (3.2%) in the second week of life of broilers, aspergillosis in the first week (1.0%) and gout caused similar percentage of mortalities in the first and second week of life. Microscopic changes were predominately characterized by congestion, hemorrhage, infiltration by various inflammatory cells especially heterophils, focal granulomatous reaction in aspergillosis and urates in the tubular parenchyma in the form of pink amorphous radiating material surrounded by a narrow zone of inflammatory cells in cases of visceral gout.

Conclusion:
Salmonellosis, colibacillosis, aspergillosis and gout were diseases mainly responsible for early chick mortality in broilers. Colibacillosis was responsible for causing highest early chick mortality followed by aspergillosis, salmonellosis and gout.

Key words: Early chick mortality, Colibacillosis, Salmonellosis, Aspergillosis, Broilers