Effect of Light Regime and Age on Reproduction of Turkeys ,

IT HAS been demonstrated by numerous investigators that the turkey female becomes refractory to photostimulation when exposed to 13 or more hours of continuous daily light for prolonged periods of time: Harper and Parker (1957, 1960, 1962), McCartney et al. (1961), Leighton and Shoffner (1961a, b), and Shoffner et al. (1962). It has also been demonstrated by the above workers that the female turkey must be subjected to a period of short days followed by increased or increasing day length in order to be stimulated into satisfactory levels of egg production. Hens that are in egg production will, in most cases, cease production when subjected to a series of short days as shown by Harper and Parker (1957). Their data also showed that when yearling hens were restricted to 9 hours of light per day for a 4 week period and subsequently exposed to 17 hours of light per day…