Broiler Breeder Egg Shape

To determine the influence of egg shape on the hatchability of eggs set with their air cells upwards or air cells downwards, 600 “pole distinguishable” eggs (D) and 600 “pole indistinguishable” eggs (ID) were divided equally among the two air cell incubation treatments. Egg shape influenced the hatchability of embryos differently depending on the air cell incubation treatment. D-air cell down (DD) eggs did not hatch as well as D-air cell up (DU) eggs (54.3% vs. 71.1%, respectively); however, ID-air cell down (IDD) and ID-air cell up (IDU) eggs hatched equally well (62.8% vs. 65.4%, respectively). This interaction between egg shape and air cell incubation treatment was due to the decreased hatchability of IDU eggs compared to DU eggs and the increased hatchability of IDD eggs compared to DD eggs. Air cell incubation treatment alone influenced the incidence and types of malpositions of dead in shell embryos, while both shell shape and air cell treatment influenced the frequency and type of malpositions of pipped chicks.