Egg‐shell water Vapour conductance of the domestic fowl: Comparison between two breeds and their crosses

Abstract

1. A comparison of egg water loss and egg‐shell water vapour conductance was made between the Sinai fowl (a desert inhabiting breed) and the commercial White Leghorn, together with their reciprocal crossbreds.

2. The Sinai egg was found to be smaller and less permeable to water vapour than the eggs of the Leghorn and crossbreds. The differences were statistically significant.

3. The measured egg‐shell water vapour conductance of the Sinai breed was 25% lower than predicted on the basis of egg mass.

4. The low permeability of the Sinai egg shell might be related to its higher than predicted thickness, which did not interfere with the shell functional pore area.

5. The low water vapour conductance of the Sinai egg shell may reflect adaptations to its dry habitat.