The Effect of Constant and Fluctuating Environmental Temperatures on the Biological Performance of Laying Pullets

Abstract

INVESTIGATIONS of the seasonal variation of egg production in different geographic locations (for reviews see Huston et al., 1957; Ragab and Assem, 1953) have led to the conclusion that high environmental temperature is one of the major causes of the decline in egg production during summer. In most of these studies it was difficult to separate the effect of age from the effect of the seasonally changing environment. The results of experiments with layers of the same age are less conclusive. Warren et al. (1950) found little difference in annual egg production between an uncontrolled environment, where the mean daily temperatures ranged from about 30°F. in winter to about 85°F. in summer, and a controlled environment where a constant temperature of 65°F. was maintained. Huston et al. (1957) reported that White Leghorn hens laid as well at a constant temperature of 90°F. as hens kept in an environment where mean…