Artificial increase of eggshell conductance improves hatchability of early laid goose eggs

1. The purpose of this work was to test the possibility of increasing the hatchability of goose eggs with low mass specific eggshell gas conductance (G_sp), by drilling holes through the eggshell into the air cell, and thus solving both the low water loss rate and low oxygen availability problems. 2. A linear relationship was found between the area of a hole drilled and the apparent increase in eggshell gas conductance (G). Drilling more than one hole increased apparent G 3·6 times more than one hole only, of the same total area. 3. Hole-drilling did not increase egg contamination. The drilling of a 5 mm² hole on day 17 of incubation increased hatchability both in laboratory tests and in commercial hatcheries (6·1% and 10·5% respectively). 4. Drilling holes on days 15 to 22 of incubation increased hatchability when the predicted mean water loss was lower than 14%. Drilling on day 25 did not have a significant effect, and drilling on day 11 of incubation was too early. 5. Drilling a hole into the aircell (during the second half of incubation) may increase hatchability of low conductance eggs, although oxygen pressure under the eggshell should then be checked in order to evaluate oxygen availability to the embryo.