Effects of Feeder Space and Feeding Programs During Rearing and Laying on Broiler Breeder Reproductive Performance and Livability

A series of four experiments were conducted in slat-litter pens in order to determine the effects of feeder space, feeding programs during rearing and laying, strain, and length of starter feed on broiler breeder female reproductive performance, uniformity, mortality, and progeny performance.;In Experiments I and IV, there was an increased feeder space between the rearing and laying periods but no change in Experiment III. In Experiment II, an increased, decreased, or no change in feeder space were compared. Irrespective of other treatments, maintaining similar feeder space between rearing and laying periods produced better egg production and generally lower hen mortality during the laying period. Feeder space also did not affect the uniformity of body weight nor livability during rearing.;Line and Sigmoid feeding programs during rearing were compared in Experiments III and IV. In Experiment III, the Sigmoid and Line program hens exhibited similar rates of lay but Sigmoid hens produced greater EHH due to lower female mortality during hot weather while no effect was observed in Experiment IV.;Fast and Slow feeding to peak production programs were compared in Experiments I, II, and III. The Slow feeding to peak program produced lower female mortality in the presence of hot weather early in the laying period and a large increase in feeder space in Experiment I as compared to no change in feeder space and later hot weather in Experiment III. Additionally, the Slow feeding to peak program produced numerically lower female mortality in Experiment II.;There were no significant effects on hatchability of fertile eggs in Experiment II and IV, but the Ross 708 strain and Sigmoid rearing program hens exhibited improved hatchability of fertile eggs in Experiment I and III, respectively.;An increased feeder space in Experiment I significantly decreased egg weight at 28 and 30 wk of age but had no effect on broiler performance. The Fast feeding to peak approach significantly increased yolk weight, decreased albumen weight, and changed the yolk:albumen ratio in Experiment II. In Experiment III, where there was no change in feeder space, greater egg weight at 28 wk produced by the Slow feeding to peak was observed. This larger egg weight produced male broilers with poorer adjusted feed conversion ratio and greater mortality but this may have been a residual effect due to hotter eggs caused by the lack of proper temperature control during incubation.;In the individually caged hens of Experiment V, an increased albumen height due to the Fast feeding to peak program and the Ross 708 strain was observed. The thicker albumen may have slowed vital gas diffusion during incubation and resulted in smaller broiler progeny that exhibited greater mortality.;It can be concluded that increase or decrease in feeder space at photostimulation can have a detrimental effect on reproductive performance and mortality of broiler breeder females. A Slow feeding to peak program as well as Sigmoid feeding program during rearing improved percentage hen mortality during hot weather. Consumption of a greater quantity of crude protein in early life also produced lower female mortality during the laying period.