EFFECT OF STOCKING DENSITY ON PERFORMANCE OF MODERN BROILER BREEDS

Stocking density is an important economic factor in broiler production. As high stocking densities as well as low stocking densities may influence the profits of the production an optimal stocking density of 32 kg/square meter was postulated, some years ago. Meanwhile, rearing conditions and genetic profiles of breeds have changed. Therefore, experiments were started to test whether this advised value may still be valid. Two trials were done with the additional factors climate (bad, good), flock size (big, small) and breeds (3) besides stocking density (loose, middle, tight). Stocking density was varied in the two trials between 20 and 29 birds per square meter and 18 and 26 birds per square meter, respectively. Fattening performance and carcass quality defined as proportion of carcasses in grade B were used for judgement. In trial 1 fattening performance was not influenced by a bad climate, although concentrations of noxious gases were high. Under high stocking density weight gain was reduced and feed conversation was improved. Under bad climate this was more visible. According to this, the proportion of grade A carcasses was lower under bad climatic conditions. Defects of carcass quality were less common under moderate stocking densities. In trial 2 the same relationships between fattening performance and stocking densities occurred as in trial 1. The flock size had no distinct effect on fattening performance. Defects of carcass quality were more common under high stocking densities and small flock sizes. Differences in breeds were observed, as well. Breast blisters and leg deformations were the most common defects. The results of the trials show that high stocking densities may reduce weight gain, whereas carcass quality may not be influenced in the same way. Therefore, ist is advised to apply an optimal stocking density of 35 kg/square meter, up to fattening periods of 6 weeks.