Relationship of Eggshell Porosity to Stage of Embryonic Development in Broiler Breeders ,

Broiler breeder eggs with early dead (ED) embryos possessed significantly thinner membranes and significantly thicker eggshells than were observed for shells from eggs that hatched (H), were pipped (P), or contained late dead (LD) embryos (eggshell type). Overall pore concentration was significantly greater in H than in ED eggshells and significantly greater in ED than in LD or P eggshells. At the large end, eggshells from H eggs exhibited a significantly greater pore concentration compared to all other eggshell types. Pore concentrations at the equator and small end were significantly greater in H and ED eggshells when compared to eggshells from LD and P embryos. Large end pore concentration was significantly greater than at either the equator or small end in H eggshells. Optimum hatchability may depend on a proper eggshells region-pore concentration relationship as well as a sufficiently high number of pores in all three regions of the shell. Embryonic mortality may result from insufficient pore numbers. An excessively thick shell, which may negate the compensatory effects of high pore numbers at the equator and small end, may account for some ED embryos.