Development of uterine chick embryos after storage at 5 degrees C for 15 hours

Eggs obtained from the uterus of hens by hormonal administration 14 to 10 h before expected oviposition were kept at 5 degrees C for 15 h. Forty-two of these uterine eggs were incubated as whole eggs; in the case of a further 70 eggs the blastoderms were isolated and incubated whilst immersed in liquid egg albumen. Thirty-two of the eggs incubated whole (76%) developed to the primitive streak stage, but only 6 of the incubated blastoderms (9%) reached this stage of development.