Effects of 5 days of hypoxia on the blood of chick embryos

Chick embryos of 2–14 days of age were incubated in 13% oxygen for 5 days. Experimental embryos demonstrated lowered red blood cell levels, enhanced mean erythrocyte volumes, greater percentages of immature red blood cell stages, and depressed embryonic weights and stages when compared with their controls. Generally, embryos older than 13 days at the termination of the hypoxic incubation were less affected by the low oxygen treatment than younger ones.