Intraspecific variability in early embryogenesis in fowls with special reference to the resistance of embryos to the action of low temperatures (Russian)

Differences in variability of fowl embryos at laying, and after 2 days incubation were demonstrated. The resistance of non incubated blastodisks to the effect of low temperatures depends on the level of differentiation at the initial stages. Those species and strains in which less developed embryos predominate at laying, proved to be the most resistant to suboptimal conditions. Groups with the most differentiated blastodisks showed the greatest resistance to the effect of extremely low temperatures. Intraspecies differences in the resistance of embryos are explained by genetic differences in their variability.