Effect of Frequent Turning on Hatcha- bility and Distribution of Embryo Mortality*

FACTORS affecting hatchability may be divided into those which are concerned with the breeding of the parent stock, the nutrition of the parent stock, and the en-vironmental and mechanical factors which are involved in the care and the incubation of the eggs. This paper is concerned with the study of one mechanical factor, namely, the effect of the number of times that the eggs are turned, on the distribution of em-bryo mortality and on hatchability. The earliest work on the distribution of embryo mortality was that of Payne (1919) on the domestic fowl. He found that there are two distinct periods of high mortality, the first on the fourth day and the secon