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, G(sp), 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 G(sp) may cause sub-optimal egg water loss which increases late mortality. 4. Mean G(sp) 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 G(sp) thus increases hatchability.