One hundred and eighty one-day old broilers (Arbor Acres) were used in this study. The chicks were divided into three groups: Group 1 where the chicks were reared under continuous light (CL); Group 2 where the birds were reared under increasing lighting program (INL); and Group 3 where the birds were reared under intermittent lighting program (IL). The birds were kept under these lighting programs till 7 weeks of age. The obtained results could be summarized as follows: The INL decreased body weight (BW) at 7 weeks of age as compared to CL, while IL birds attained similar body weights to CL. The overall mean indicates that broilers reared under CL and IL showed a significantly higher daily weight gain than those reared under INL. The overall mean of feed consumption (FC) in group 2 decreased significantly (P<0.05) as compared with groups 1 and 3. The broilers of group 2 had significantly better (P<0.05) cumulative feed conversion ratio (FCR) than that of birds of group 1, while birds of group 3 had an intermediate cumulative FCR. The mortality rate (MR) was 11.7, 8.3 and 10.0 % for groups 1, 2 and 3, respectively.
Broilers reared under IL had significantly less breast yields than those reared under CL or INL. No significant differences were observed in carcass weights, head, neck, drumsticks, femurs, wings, back, internal organs weights and abdominal fat deposition among different lighting programs. Birds of groups 1 and 3 had significantly higher fat deposition in drumstick and femur meat than those of group 2. However, there were no differences in breast fat deposition among all groups. Red blood cells (RBCs) decreased significantly (P<0.05) in birds subjected to CL than that of birds reared under INL or IL. Hemoglobin (HG) concentration was increased significantly (P<0.05) in group 2 as compared to birds of groups 3 or 1. Also, birds of group 3 had higher HG concentrations than group 1. The heamatocrit (HC) showed a similar trend as that of HG. The birds reared under CL had more leg problems than birds reared under INL and IL. It was concluded that increasing lighting program was more economically efficient than intermittent or continuous lighting programs at rearing broilers to 7 weeks of age.