[Effect of density during the raising of broilers on their morbidity and mortality]

Studied was the effect of biotic ecologic factors and their dynamic at varying density of raising broilers at equal abiotic factors. The experiments were carried out in two production buildings of the same type. A cage of low density (16.6 birds/m2) was placed on a premise of high density (23.6 birds/m2), and vice versa--a cage of high density (23.6 birds/m2) was placed on a premise of low density (16.6 birds/m2). It was found that density of raising had a definite bearing on both morbidity and mortality rates. At lower density they ranged from 6.84 to 9.74 per cent, and at higher density--from 10.67 to 14.07 per cent, whereupon by the end of the fattening period certain changes were observed in the behaviour of birds (anxiety, inadequate locomotion movements). Diseases that were transmitted transovarially and diseases such as cannibalism affected greater number of birds when these were raised at higher density. It was concluded that density of raising influenced both the abiotic and biotic factors, and its integral effect could be evaluated as that of a stress factor when higher numbers of birds were raised on unit area. This invariably had a bearing on the rates of morbidity and mortality. The approach that has been used so far in optimizing the microclimatic parameters only (at higher density of raising) was shown to be partial as the effectiveness of production is governed by the action of biotic factors as well. This makes it necessary to study their effect.