The Effect of Stocking Density on Stress Reaction in Broiler Chickens during Summer

The aim of this study was to investigate the effect of stocking density on the heterophil to lymphocyte ratio (H:L), blood corticosterone concentration, immune response, and some performance parameters in broilers during summer. In all, 300 1-dayold commercial broiler chicks (Ross 308) were housed at densities of 15, 20, and 25 birds/m, with 2 replicates of each. H:L ratio and blood corticosterone concentration were used to measure the level of stress in the birds. Newcastle disease (ND) antibody titers were also analyzed to determine the level of immune response with a commercial ELISA kit. Mean H:L ratio, corticosterone concentration, and Newcastle disease antibody titer (log10) on day 42 were 0.41, 0.43, and 0.45, 3.81, 4.13, and 4.39 ng/ml, 3.99, 4.10, and 3.88, respectively, for birds housed at 15, 20, and 25 birds/m. Stocking density had no significant effect on H:L ratio, blood corticosterone concentration, immune response, and some performance parameters in broiler chickens. Consequently, high yield per unit area could be achieved with different stocking densities (15, 20, and 25 birds/m) in broiler production during summer.