A longitudinal study design was used to assess the major causes of chicken mortality in chicken reared under extensive and small scale intensive production system in Tiyo district. Semi-structured interview, follow up assessment and coprological and bacteriological examinations were used to collect information on potential causal factors. Follow up study was conducted to assess the incidence of diseases and mortality rate during both dry and wet seasons. The overall mortality rate for chicken reared under extensive and intensive production systems were 3.7% and 5.2%, respectively. Diseases, mismanagement, predators, bad weather condition and cannibalism were the major causes of chicken mortality. Coccodia Coccidiaspecies, Heterikasgalinarum Heterakisgallinarumand Railientinacesticillus Raillietinacesticilluswere the main internal parasites identified relatively at high proportion. Chicken mortality was statistically associated (P < 0.05) with age and season of the year. Provision of trainings and extension service for farmers and those individuals involved in poultry production activities and improving overall management system have paramount importance in alleviating the existing problems.

Keywords: chickens, mortality, longitudinal study