Intermittent Light and Restricted Feeding of Broiler Chickens

A light control study in conjunction with feed restriction was conducted with 1600 meat-type chickens housed in 32 pens with sexes separate. All groups received continuous light of 50 lux for the first 7 days. Light intensity was reduced at weekly intervals to 3 lux at 4 weeks of age which was maintained to 8 weeks. Four light treatments were utilized. CL (continuous light); 1:2 (hours light: dark); .25:1.75; and DLR (decreasing light ratio as follows: 2:1 from 8 to 14 days, 1.5:2.5 from 15 to 21 days, 1:2 from 22 to 28 days, .5:2.5 from 29 to 42 days, .25:1.75 from 43 to 56 days). Feed treatments were full-fed and restricted (85% of full-fed from 15 to 42 days). No differences between light regimes for 8-week body weight of females were noted; however, the males under 1:2 were heavier than CL and DLR regime males. Poorer feed efficiency was noted with CL in females and also when compared to DLR with males. No differences in dressing percentages were noted between light treatments. Intermittent light groups tended toward more abdominal fat, especially in the females. During the period of feed restriction (14 to 42 days) greater gains and better feed efficiencies were noted for the full-fed groups than for the restricted groups; however, from 43 to 56 days when all were full-fed this was reversed. Dressing percentage was greater with less abdominal fat for full-fed males than for restricted. Broilers subjected to the restricted feed treatment exhibited considerable compensatory growth, however, 8-week body weights were significantly reduced.