Compensation for seasonal changes in eggshell conductance and hatchability of goose eggs by dynamic control of egg water loss

1. The water loss for optimal hatchability of goose eggs was 12% of initial egg mass. 2. Mass specific eggshell water vapour conductance, Gsp, increased by approximately 50% over about 13 weeks during the winter breeding cycle. A similar increase occurred over 8 weeks during summer. 3. Constant setting of humidity in goose incubators and changes in mean Gsp may cause sub-optimal egg water loss which increases late mortality. 4. Mean Gsp was measured for every batch from each flock. Humidity was changed accordingly in order to reach optimal water loss. A significant improvement of 6% in hatchability and of 8% in Class-A goslings was noted during 14 successive weeks compared with the previous 11 weeks. 5. Dynamic humidity control for optimising water loss according to mean batch Gsp thus increases hatchability.