Effects of photostimulatory light intensity on ovarian morphology and carcass traits at sexual maturity in modern and antique egg-type pullets.

The effects of light intensity during sexual maturation on ovarian and carcass morphology at first oviposition [sexual maturity (SM)] were examined in two Single Comb White Leghorn (SCWL) strains. A modern commercial layer strain (COMM; Shaver Starcross 288) and an antique randombred control strain (ANT) were used to compare the effects of changes in laying stock on their response to varying light intensities from photostimulation (PS) until SM. Two hundred pullets from each strain were reared following COMM breeder guidelines.

Carcass traits, ovarian morphology and egg laying characteristics in early versus late maturing strains of commercial egg-type hens.

Three hundred commercial Single Comb While Leghorn (SCWL) pullets of two strains differing in age at first oviposition (early maturing = EARLY; later maturing = LATE) were reared and photostimulated at 18 wk. Selected birds of each strain were killed at weekly intervals from 17 to 23 wk, at sexual maturity, or at 68 wk of age for the study of carcass and reproductive organ traits. Egg production was recorded for surviving hens to 68 wk of age.