The effect of accidental pre-lighting of turkey hens on subsequent reproduction

The length of the light day was accidentally increased from nine hours to continuous light on one group of thirty-week old hens for an unknown period of not more than eleven days. Egg production, after attaining a level of twenty-five percent, ceased five weeks later as the result of restricting the length of the light day to four hours and two series of feed and water deprivations. One month later hens from the pre-lighted and control groups were brought into egg production. Pre-lighting depressed later egg production more in medium-bodied hens than in large-bodied hens. The major effect of pre-lighting was to reduce the length of a laying period included 9 weeks later with no significant effects on intensity of lay, number of broody periods or average length of the broody period. It was concluded that the egg production would not be greatly reduced by pre-lighting under the above conditions if the length of the laying period were shortened from 180 days to a normal 140-day period.