Impact of stocking density on the welfare and productivity of broiler chickens reared to 34 d of age

Abstract

Re-evaluating management practices to highlight opportunities for improving bird welfare is a necessary response to changing genetics, evolving standards, and increasing consumer interest in how poultry is raised. The aim of this study was to evaluate the impact of stocking density (SD) on the welfare and productivity of broilers. The SD treatments were 31, 34.5, 38, and 41.5 kg/m2. Litter moisture decreased and footpad dermatitis improved as SD was reduced, indicating an improvement in welfare. Results from the novel object test suggest birds reared at lower SD were less fearful. Heterophil/lymphocyte ratios were highest in the 31 and 41.5kg/m2 treatments, indicating these birds experienced more chronic stress. At 20 d as SD was decreased, birds spent more time at the drinker and less time resting. When older (31 d), birds preened more in the 31 and 41.5kg/m2 treatments. Stretching behaviour decreased while ruffling increased at lower SD. Final body weights were heaviest in the 31 and 34.5 kg/m2 treatments. Overall, body weight gain increased as SD was reduced, and feed intake was greatest in the 34.5kg/m2 treatment. From 21-24 d, infectious mortality was reduced in the low SD treatments. The impacts of SD are dependent on environmental management; however, even under research conditions, differences between treatments were observed. The results of this study suggest that reducing SD for broilers results in improved welfare and performance as evidenced by reductions in litter moisture, footpad dermatitis, fear, stress, and infectious mortality as well as greater market body weights and feed consumption.