Studies in Hatchability: IV. The Effect of Intercrossing Inbred Strains of Chickens on Fertility and Hatchability

Abstract

In a previous paper, the author (1929a) presented data showing that as close inbreeding is continued in chickens hatchability decreases. The kind of inbreeding practised was full-brother-and-sister and half-brother-and-sister matings. It was observed that hatchability results are affected to a greater extent in the first year of such close inbreeding than in successive years, though there is a general decline in hatchability each year that such close inbreeding is continued. Similar results were secured in Barred Plymouth Rocks and White Leghorns. In another paper, the author (1929b) determined that hatchability decreases as the coefficients of inbreeding increase.Since the intercrossing of highly inbred strains of corn produces a remarkable state of rejuvenation, as demonstrated by East and Jones (1919), it was decided to determine the effect of intercrossing the inbred strains of Barred Plymouth Rocks and White Leghorns.Originally four pens each of the two breeds mentioned were started in .