Gas Exchange of Avian Eggs with Special Reference to Turkey Eggs

Surveying the gas exchange of avian eggs shortly before hatching, one finds certain functions that are common among various precocial species and that suggest a basic strategy of development independent of the size of the egg or its incubation time. These common characteristics at time of hatching can be described as follows: 1) The total amount of O2 that will have been consumed is about 100 ml O2 · g−1 and equivalent to a caloric expenditure of .5 Kcal · g−1. 2) The O2 concentration in the air cell shortly before pipping will have fallen from 21% initially to 14%, while the CO2 concentration will have reached a value of about 6%. 3) Eggs will have lost about 15% of their initial mass due to the loss of water vapor, yet their relative water content will still be the same as when they were laid. These common end results require a precise pore geometry