Monday , January 24 Environment / Management Room : B 314

Animal welfare has generated concerns from both domestic and global market sectors. In growout, stocking density has been regarded as an area of interest for food retailers and wholesalers with welfare audits. This study examined four stocking densities on responses of male broilers during a 49d production cycle. Two trials were conducted and results were pooled. In each trial, 1,488 male chicks were randomized across 32 floor pens to simulate a final density of 30, 35, 40, and 45 kg/m2 based on a projected final BW of 3.29 kg. Growth rate and nutrient utilization were similar from 1 to 35 d of age. From 33 to 49d, BW gain (P=0.005), feed consumption (P=0.009), feed conversion (P=0.014), and the incidence of mortality (P=0.029) were adversely affected by increasing density from 30 to 45 kg/m2. Collectively, these differences were also apparent for BW (P=0.011), BW gain (P=0.011), and feed consumption (P=0.029) from 1 to 49d. The reduction in cumulative BW gain due to density can be largely explained by feed consumption. Litter moisture content (P=0.025) and foot pad lesion score (P=0.001) increased linearly with increasing density. Upon processing, weights of the whole carcass (P=0.070) and pectoralis major breast muscle (P=0.079) were decreased as density increased from 30 to 45 kg/m2, but their yields, relative to BW, were not affected. The proportion of birds with scratches on the back and thighs (P=0.021) of the whole carcass increased as density increased. These results indicate that increasing density beyond 40 kg/ m2 adversely affects BW gain, feed conversion, and meat recovery of broilers approximating 3.2 kg.