Correlation between Internal and External Egg Quality Indicators in the Early Phase of Hy-Line Brown Laying Hens

This study investigated correlations between egg quality indicators to identify external egg quality traits to predict internal egg quality using non-destructive and convenient measurements. Thirteen indicators, including Haugh unit, albumen height, eggshell breaking strength, eggshell thickness, eggshell color (CIE L*, CIE a*, CIE b*), and reflectivity value, egg weight, egg length, egg width, shape index, and yolk color, were investigated. A total of 180 brown eggs were obtained from one 27-week-old flock of Hy-line brown-laying hens raised in a cage system. Correlations were evaluated using Pearson’s correlation coefficient (r). The results showed strong correlations between Haugh unit and albumen height, eggshell color CIE L* and reflectivity, egg weight and width, egg weight and length, eggshell color CIE L* and CIE a*, eggshell color CIE a* and reflectivity, and shape index and egg length (P<0.001). Moderate correlations were observed between eggshell breaking strength and eggshell thickness, eggshell color CIE a* and CIE b*, and shape index and egg width (P<0.001). Eggshell color CIE L* was correlated with eggshell breaking strength (P<0.01), and eggshell color CIE a* was correlated with Haugh unit, albumen height (P<0.01), and eggshell breaking strength (P<0.001). The present study showed significant correlations between eggshell color and other quality indicators. Thus, this study suggests that eggshell colors based on reflectiveness and the CIE L*a*b* value can be used to estimate the Haugh unit, albumen height, eggshell breaking strength, and thickness.