Effect of Egg Weight on Eggshell Thickness, Pore Density and Chick Quality in Broiler Breeder Flock

The objective of this research was to investigate the effect of egg weight on eggshell thickness, pore density and chick quality in broiler breeder flock. Additionally the correlations between the studied characteristics were calculated. Hatching eggs were collected from 40 wk old Ross 308 broiler breeder flock. The eggs were selected, weighed and numbered individually in light (54.71-58.88 g) and medium (58.24-60.62g) weighed egg groups. Eggs were incubated at 37.5°C and 55% RH in an incubator for 18 days. On 18th day eggs were individually weighed to calculate the egg mass loss. Then eggs were incubated at 37.0°C and 60% RH in a hatcher until hatch. At hatch chicks were weighed individually and chick length was measured. Additionally egg shell thickness and pore density was determined. Egg weight loss was found non-significant in both light and medium weighed egg groups (P>0.05). Egg weight had significant effect on eggshell thickness (P<0.05). Eggshell thickness was found higher in light weighed eggs than in medium weighed eggs (P <0.05) whereas, pore density was determined higher in medium weighed eggs (P<0.01). At hatch chick weight increased with the increased egg weight (P <0.05) while as chick length was not affected by egg weight. A significant correlations was observed between initial egg weight and average eggshell thickness (r= 0.551), chick weight (r=0.615), and also between average eggshell thickness and chick weight (r=0.484) in medium weighed eggs (P<0.05)