The effect of different photoperiods and stocking densities on fattening performance, Carcass and some stress parameters in broilers

This study was carried out for the purpose of investigating the effects of different photoperiods and stocking densities on physiologic parameters such as body weight, feed consumption, feed efficiency, carcass traits and some stress parameters in broiler chickens. Throughout the experiment, 480 day-old male chickens obtained from a commercial hatchery were used. The chicks were placed in different partitions which had three different photoperiod (continuous lighting: 24 hour light, constant lighting: 16 hour light - 8 hour dark, intermittent lighting: 4 hour light – 2 hour dark) were applied. Each photoperiod group was formed with five replicates at two different stocking densities (normal stocking density: 12 broiler/m2, high stocking density: 20 broiler/m2). The experiment was carried for 42 days. At the end of the experiment, the effect of photoperiod and stocking density on live weight gain were significant (P<0.05) while photoperiod significantly affected the feed consumption only (P<0.05). The feed efficiency were insignificant (P>0.05) with respect to both factors. The photoperiod programs had significant effects on the relative weight of gizzard, blood, feather percentage values (P<0.05) and breast percentage values (P<0.01). The stocking density has a significant effect on relative heart weight (P<0.05) and entire thigh values (P<0.01). At the end of the experiment, it was ascertained that the photoperiod program and stocking density had no significant (P>0.05) difference on tonic immobility and tibial dyschondroplasia values. However, stocking density had a highly significant effect (P<0.01) on gait score values and on heterophil-lymphocyte rate values (P<0.01).