Effects of photostimulatory lighting and feed allocation in female broiler breeders. 2. Egg and chick production characteristics

Changes in egg production, chick production, and egg laying patterns were examined in individually caged female Shaver Starbro breeders in a 2 x 2 factorial design based on two photostimulation programs and two feeding programs. The light period of fast photoperiod (FP) hens was changed from 8L: 16D to 15L:9D at 20 wk of age. Slow photoperiod (SP) hens were switched from a 8L:16D photoperiod at 20 wk to 1 1L:13D, with increases to 12L: 12D, 13L:11D 14L:10D, and 15L:9D weekly to 24 wk of age. Slow feed (SF) hens were provided small (5 g or less) weekly increases in feed allocation from 20 to 25 wk. Fast feed (FF) hens received larger feed allocations from 20 to 2S wk (maximum difference of 25 g more feed than SF hens received). Individual body weight, egg production, sequence length profiles, fertility, and hatchability were monitored to 64 wk of age. Whereas all treatments hd a high rate of egg production, total egg production was 10.9 eggs greater in the SF feeding program (200.3) compared to the FF program (189.4). Hen-day production of SF birds was 68.2% for the laying period compared to 64.5% for FF birds over the 42 wk laying period. The mean laying sequence length of SF birds was 36.4% longer than for FF birds, indicating superior egg laying patterns and ability to maintain egg production. Sequence length was longer in FP than in SP hens in early lay (22 to 35 wk of age), although this effect appeared to be transient. Hatch of fertile and hatchability were increased in the SP compared to the FP birds, indicating an advantage to the SP program with regard to total number of chicks produced. Examination of embryonic mortality by 7-d periods of incubation indicated that the FF birds had a higher incidence of early and mid-term embryonic mortality than the SF birds, possibly relating to developmental problems associated with eggs of birds with excessive follicle development. These data demonstrate that minor differences in feed allocation can have an influence on egg and chick production traits and that precise early breeder hen management is paramount to optimize chick output. Exposing 20-wk old pullets to small, multiple feed increases can increase egg production.