Effect of Varying Light Intensity on Welfare Indices of Broiler Chickens Grown to Heavy Weights

Interactive effects of light-sources, photoperiod, and strains on growth performance, carcass characteristics, and health indices of broilers grown to heavy weights1

Effects of light sources, photoperiods, and strains on growth performance, carcass characteristics, and health indices of broilers grown to heavy weights (>3 kg) were evaluated. The experimental design was a 4 × 2 × 2 factorial treatments consisting of 4 light sources [incandescent (ICD, standard), compact fluorescent light, neutral light emitting diode (Neutral-LED), and cool poultry specific LED (Cool-poultry specific (PS)-LED)], 2 photoperiods (regular/intermittent [2L:2D], and short [8L:16D]), and 2 strains (A, B). In each trial, chicks of 2 different strains from different commercial hatcheries were equally and randomly distributed into 16 environmentally controlled rooms at 1 D of age. Each room was randomly assigned one of 16 treatments from day 1 to 56 D of age. Feed and water were provided ad libitum. Birds were provided a 4 phase-feeding program (starter, grower, finisher, withdrawal). Birds and feed were weighed on 1, 14, 28, 42, and 56 D of age for growth performance. On day 56, a total of 20 (10 males and 10 females) birds from each room were processed to determine weights and yields. The BW, BW gain, live weight, and carcass weight of birds reared under PS-LED were higher (P < 0.05) in comparison with birds reared under ICD, but feed intake, feed conversion ratio, mortality, and carcass characteristics were not affected by treatments. Also, broilers subjected to the short/non-intermittent photoperiod had the lowest (P < 0.05) growth performance and carcass characteristics compared with values obtained for regular/intermittent photoperiods. In addition, strain was significant (P < 0.05) for most of the examined variables. Feed conversion, fat, tender, and yield were not affected by treatments. There was no effect of photoperiod, light sources, or their interactions on mortality. This study shows positive impacts on alternative light sources when compared to ICD along with regular/intermittent photoperiod in commercial poultry facilities rearing the 2 strains used in this study, thereby reducing energy costs and optimizing production efficiency without compromising the welfare of broilers grown to heavy weights.