The Effect of Age at Lighting on Egg Production and Pausing in Turkey Hens

Abstract

In each of 2 experiments, 4 groups of Broad Breasted White turkey hens were hatched at 2-week intervals and given a 6-week period of restricted light (8L-16D) when 24, 22, 20 and 18 weeks of age. The hens were given stimulatory light (16L-8D) when 30, 28, 26 and 24 weeks of age, respectively. There was a delay of 5 days in onset of lay in hens lighted at 24 weeks of age, as compared to those lighted at 30 weeks. Mean age at sexual maturity was 234, 221, 209 and 197 days of age, respectively, for hens lighted at 30, 28, 26 and 24 weeks of age. In test 1 (1971), hens given stimulatory light at 30 weeks of age produced significantly more eggs in a 140-day production period than did hens lighted at 26 or 24 weeks of age. A similar but nonsignificant trend was noted in test 2. The youngest hens (26 and 24 weeks of age) were lighter in weight and initially laid smaller eggs than hens lighted at 28 and 30 weeks of age. Approximately 53 percent of the 2 youngest hatches of hens paused 1 or more times in lay as compared to about 30 percent of the hens in the 2 older hatches. A comparison of egg production between hens pausing and those not pausing during the 140 days of lay indicated that pausing accounted for a loss of about 27 eggs per hen. Pausing hens had fewer and smaller egg sequences than did nonpausing birds. Age at lighting had no appreciable effect on fertility and hatchability of eggs laid during the second 10-week period of lay.