The Effect of Restricting Light During the Adolescent Period on Reproductive Performance in Turkeys Subsequently Exposed to a 12-, 14-, and 20-Hour Day

ARTIFICIAL illumination has been extensively used with chickens for decades; for evidence of this fact one needs only to refer to the classical review by Whetham (1933). In the ensuing years since her review, research on artificial lighting of poultry has been sporadic until the report by King (1958) on “stimulighting.” In turkeys the research by Asmundson et al. (1946) and Asmundson and Moses (1950) indicated the necessary optimums of light intensity and total day for normal reproduction of mature spring hatched turkeys. Currently there has been increased interest in year around turkey productions so that another factor in illumination, namely light-conditioning or light-restriction is being investigated in order to bring hens into egg production during the summer and early fall months (Harper and Parker, 1957). This paper reports the conditioning effects of short days, 6 and 10 hours, respectively, for a period of 3 weeks beginning at age 20 …