The effect of the rearing system and the genotype of laying hens on the eggshell quality at different phases of the laying period

Abstract

Eggshell quality can be crucial for success in poultry production. This applies particularly to the alternative rearing systems of laying hens. For this reason, experimental research was conducted with the aim to evaluate the effect of rearing system, genotype and hen's age on the eggshell quality. Isa Brown and New Hampshire were genotypes used in this study. These two genotypes were housed in floor and organic rearing systems. Eggs were collected for analyses in three different phases of the productive activity (at the beginning of the laying period - 24 weeks hen's age, in the middle of the laying period - 48 weeks hen's age, and at the end of the laying period - 72 weeks hen's age). In these samples (fifteen eggs per group) were investigated eggshell quality parameters: weight, proportion, thickness, deformation and breaking strength. There was no significant effect of the rearing system on the observed parameters (p≥0.05) in the 24 week hen's age, while Isa Brown had higher weight, thickness and breaking strength but less eggshell deformation compared to New Hampshire (p≤0.05). Floor reared Isa Brown layers had a higher weight and proportion compared to the other three experimental groups (p≤0.05), as well as higher thickness but lower eggshell deformation compared to floor New Hampshire and organic Isa Brown hens in the 48 week hen's age. Organic New Hampshire hens had a lower weight, proportion and eggshell breaking strength but a higher deformation compared to the other experimental groups (p≤0.05) in the 72 weeks hen's age.