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

Changes in egg production, chick production, and egg laying patterns were e xamined in individually caged female Shaver Starbro breeders in a 2 x 2 fac torial design based on two photostimulation programs and two feeding progra ms. 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 11L:13D, with increases to 12L:12D, 13L:11D, 14L:10D, and 15L:9D weekly to 24 wk of age. Slow feed (SF) hens were provi ded small (5 g or less) weekly increases in feed allocation from 20 to 25 w k. Fast feed (FF) hens received larger feed allocations from 20 to 25 wk (m aximum difference of 25 g more feed than SF hens received). Individual body weight, egg production, sequence length profiles, fertility, and hatchabil ity were monitored to 64 wk of age. Whereas all treatments had a high rate of egg production, total egg product ion 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 layin g period compared to 64.5% for FF birds over the 42 wk laying period. The m ean laying sequence length of SF birds was 36.4% longer than for FF birds, indicating superior egg laying patterns and ability to maintain egg product ion. Sequence length was longer in FP than in SP hens in early lay (22 to 3 5 wk of age), although this effect appeared to be transient. Hatch of ferti le and hatchability were increased in the SP compared to the FP birds, indi cating 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 em bryonic mortality than the SF birds, possibly relating to developmental pro blems associated with eggs of birds with excessive follicle development. Th ese 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 p ullets to small, multiple feed increases can increase egg production.