Further Studies on Environmental and Hereditary Factors Affecting Winter Pause Incidence and Duration

THIS paper includes results of a further study of possible environmental and hereditary factors on pause incidence and duration in Rhode Island Reds. The work of Lerner and Taylor (1936, 1939, 1947) with White Leghorns is almost in complete agreement with the results reported by Hays (1926, 1936) on Rhode Island Reds. The California workers conclude that winter pause is of great economic importance, that both environmental and hereditary factors are in operation, and that the pause tendency has a rather low degree of heritability. Their latest report (1947) indicates that intensity of laying and winter pause are rather intimately associated. Particular attention has been given to incidence of pause with minor attention to pause duration. As early as 1926 Hays pointed out that pause duration was affected by intensity of laying. In 1936 Hays emphasized the relation of intensity and incidence of winter pause. Low temperatures were also shown . . .