Effect of translucency and eggshell color on broiler breeder egg hatchability and hatch chick weight

Abstract

A successful hatch has a considerable economic impact on all poultry companies. The aim of the current study was to describe the possible effects of shell translucency (T score) and coloration lightness (L* value) on shell thickness, hatchability, and chick weight. A total of 4,320 eggs from 4 commercial Ross 708 breeder flocks (50-55-wk old) were used. Eggs were selected for T score and L* value. A 3-point subjective scoring system was used for T score (1=low, 2=medium, 3=high), and an electronic colorimeter for L* value, sorting the eggs as light (avg. L*=80.7) or dark (avg. L*=76.0). Data were analyzed using the GLIMMIX procedure of SAS (V9.4) and Tukey's HSD test was performed to separate means, a significant difference was considered when P ≤ 0.05. Results suggest that the color of the eggshell was related to the egg weight on the day of collection (P=0.0056) and at transfer (P=0.0211), in both cases dark eggs were 0.6 g heavier than light eggs. Dark eggs had a 3.8% increased hatchability of egg set (P=0.0481) and yielded 6 µm thicker shells (P=0.0019) when compared to light eggs. Regarding translucency, egg weight at transfer was 0.8 g heavier for T score 1 eggs compared to T score 3 (P=0.0358). The translucency score of 1 had a 6.9% higher hatchability of eggs set (P=0.0127) and 0.7 g heavier chick weight (P=0.0385) compared to T score 3. However, T score 1 eggs had shells 28 µm thinner than the T score 2 and 34 µm thinner than T score 3 (P < 0.0001). An interaction effect was observed for eggshell thickness, L* value, and T score, where eggs classified as light with T score 1 had thinner eggshells compared to those that were dark with T score 3 (P=0.0292). These results suggest that eggshell translucency and coloration lightness can be good noninvasive indicators of eggshell thickness, hatchability, and chick weight in broiler breeder flocks.