Influence of Light Intensity on Ovulation in Turkeys

THE mature White Leghorn pullet responds to low light intensities (such as 0.5 or 1.0 foot candle) just as well as to more than 30 foot candles (Roberts and Carver, 1941; Nicholas, Callenbach, and Murphy, 1944). Turkey hens, like chickens, will start egg production earlier if artificial light is used to lengthen the day (Albright and Thompson, 1933; Scott and Payne, 1937; Charles Wilcox, Flagg and Tepper, 1938; Wilcke, 1939). Until now, apparently, no one has determined the effect of different light intensities upon the onset of ovulation in turkeys. The present paper reports data on this problem and on the response of genetically early- and late-maturing birds to artificial lengthening of the day. The need for such information became apparent in 1942 and subsequent years, when the enforced use of dim lights resulted in a less positive response (delay in starting to lay and a consequently lower initial rate . . .