The Effect of Incubating Eggs Narrow End Up on Malposition II and Hatchability

Eggs from Single Comb White Leghorns, Black Sex-links and White Plymouth Rocks were incubated in an upside down position, narrow end up for 8, 9, 10 or 17 days before turning them to the normal position with the broad end up. Six settings were incubated and eggs from each breed for each setting were used for controls. Chick embryos were able to return to their normal position, head in the broad end, in eggs that were held upside down for 8 days and then returned to the normal setting position. A significant number of embryos as compared with the 8 day eggs were locked in Malposition II after being held narrow end up for 9, 10 or 17 days of incubation. Eggs from White Leghorns, Sex-links and White Plymouth Rocks set narrow end up for 8, 9, 10 or 17 days gave a lower percent hatchability than the control eggs. Sixty-five percent of the White Leghorn eggs, 83.1% of the Sex-links eggs and 74.2% of the White Rock eggs that were in Malposition II at hatching time were able to hatch.