Evaluating the effects of a 4°C storage temperature on the eggshell quality of Hyline W-36 layers

In the United States, eggs from commercial table layers must be stored at a temperature no greater than 7°C after being packaged for consumer consumption. Understanding how the overall eggshell quality deteriorates during a 28-day storage period at 4°C is beneficial information to the commercial table industry. The objective of this study was to evaluate how a 28-day storage period at 4°C affects the translucency score (TS) and overall eggshell quality of table eggs from Hyline W-36 hens. This study was conducted with 521 eggs from 55-week-old Hyline W-36 laying hens. Eggs were collected on day 0 and washed before undergoing initial external eggshell quality parameter testing (TS, weights, and L* scores), and eggshell thickness measurements. Subsequent external quality parameter testing was conducted on days 7, 14, 21, and 28. Additional TS measurements were taken on day 1. Internal eggshell quality parameter testing (albumen height, Haugh units, yolk color, and egg grade) and breaking strength measurements were taken on days 1, 14 and 28. Data was analyzed using PROC Mixed with LSMeans when appropriate, PROC GLM with Tukey's HSD when appropriate, or a Chi-Square analysis with P ≤ 0.05. Storage duration and TS had a significant interaction effect on albumen height and Haugh units (P < 0.0001 for both variables). Eggshell thickness was only influenced by TS (P = 0.0196) with TS 1 and 2 eggs having the thinnest shells (0.460 mm and 0.462, respectively) and TS 3 eggs having the thickest shells (0.472 mm). The storage period significantly affected egg weight, L* scores, TS, yolk color, and egg grade (P < 0.0001, P < 0.0001, P < 0.0001, P = 0.0450, and P = 0.0456, respectively). The results from this study are not conclusive on the use of TS as an effective parameter for determining eggshell quality during the storage period. However, it can be concluded that overall eggshell quality does deteriorate during a 28-day storage period at 4°C.