Temperature and Viability as Related to Winter Pause Incidence and Duration

CESSATION of egg production between November first and March first of the first laying year may be called winter pause. This phenomenon has been studied by many workers but most extensively in White Leghorns by Lerner and Taylor (1936, 1939 and 1947) and in Rhode Island Reds by Hays and associates (1924, 1926 and 1936). These workers agree that pauses of seven or more days may be significant from the standpoint of inheritance. Both groups have shown that winter pause reduces annual egg production, is associated with low intensity, and is affected both by environment and by inheritance. One important objective of poultry breeders has been to reduce the incidence of winter pause as well as its duration. Hays (1944) pointed out that about 50 percent of Rhode Island Reds bred for high fecundity exhibited pauses of eight or more days with a mean duration of 36.47 days. Such a . . .