Performance evaluation of Kuroiler and Sasso chicken breeds reared under farmer management conditions in highland and lowland areas of Mvomero district, Eastern Tanzania.

One thousand one hundred and fifty-two dual-purpose improved chickens (576 Kuroiler and 576 Sasso) of mixed sexes were reared in two diverse agro-ecological zones, i.e., highland and lowland in Mvomero district, Eastern Tanzania, to determine the effects of agro-ecological zones on growth performance, egg production, and survivability under farmer management conditions. Two villages per zone were purposively selected, and from each village, 16 farmers were included in the study; a particular farmer received 18 birds of mixed sexes of the same breed. Data on body weight, egg production trait, and mortality were taken at different ages from week 6 up to 52. General Linear Models fitting breed, agro-ecological zone, and interactions between breed and zone were used to analyze the data. Results show that breed had no significant effects on body weight and body weight gain. However, the effects of the agro-ecological zone and interaction between breed and zone on body weight and body weight gain were significant at the 16th and 20th week of age. The highland zone had heavier chickens than the lowland. While Sasso performed better than Kuroiler chickens in the highland zone, the opposite was observed in the lowland. Significant breed × agro-ecology interactions were observed only for age at first egg whereby Sasso matured earlier than Kuroiler in the highland zone but much later than Kuroiler in the lowland. Birds raised in the highland zone survived better than those chickens in the lowland during both growing and laying periods. Thus, knowledge of breed performance in relation to agro-ecological differences is critical when distributing improved chicken breeds to farmers.