The influence of turning on the hatchability of hens' eggs II. The effect of turning frequency on the pattern of mortality, the incidence of malpositions, malformations and dead embryos with no somatic abnormality

Abstract

Reasons were sought for the changes in hatchability associated with varying frequency rate observed in part I and by other workers. All deadin-shell from the hatches of part I were examined and classified into a number of categories. Their varying incidence in relation to the control hatches was taken to indicate the effect of the rates of turning investigated, viz. 0, once in 2 days, 2, 6, 12, 24 (control), 48, 96, 144, 192 and 480 turns per 24 hr. to the end of the 18th day of incubation. At the observed optimum rate of turning (96 x ) mortality was reduced throughout the incubation period with the greatest reduction occurring towards the end; the incidence of malpositions and malformations was reduced as was the case of embryos with no obvious cause of death. The observed decrease in mortality and hence increase in hatchability at the optimum rate of turning was attributed mainly to the probable improvement of the embryo's physiological environment.