PS7-19. Age-dependent Effects of Supplemental Forage on Egg Quality Attributes of Barred Plymouth Rock Hens.

Abstract The U.S. egg industry is shifting toward alternative housing systems to enhance hen welfare, promote natural behaviors, and meet consumer demand for cage-free products. Barred Plymouth Rock hens are a heritage breed known for their excellent egg-laying ability and are commonly used by small- and medium-scale producers who prioritize forage access and natural behavior expression. This study evaluated the influence of forage access on egg quality attributes of Barred Plymouth Rock hens at different flock ages. Two flocks of hens, aged 80 and 108 weeks (younger vs. older), were assigned to two dietary treatments (forage vs. non-forage), with two replicates of 10 hens each. Hens were housed in outdoor pens of 8’ x 8’ hoop coops, which provide shelter while exposing the birds to natural day lengths and seasonal temperatures. Hens were allowed access to supplemental forage three times each week by introducing sprouted oat trays to the forage-fed pens. Freshly laid eggs were collected over 8 weeks for egg quality analysis, and measurements were taken for egg weights, albumen and yolk dimensions, yolk color, shell thickness, translucency score, and shell weights. Additionally, computations were done to derive the indexes, percentages, and Haugh Unit. Data collected were subjected to two-way analysis of variance (ANOVA) using Statistical Analysis Software (SAS), to evaluate the main effects of flock age, forage access, and their interactions. Treatment means were separated using Tukey’s Honestly Significant Difference (HSD) test at P < 0.05. The results showed that the older flocks had higher egg lengths and width, with reduced egg shape index (ESI) (P < 0.05) compared to the younger flocks. Access to forage increased the egg width, ESI, albumen weight, albumen length, and improved the yolk color better than unfed hens (P < 0.05). The albumen height, albumen index, and Haugh Unit were higher in eggs from younger flocks regardless of forage access (P < 0.05). Compared to the younger flocks, the yolk length and weight were increased in older flocks (P < 0.05). The shell parameters indicated that the translucency score of eggshells was unchanged with flock age and forage access (P > 0.05). However, the eggshell weight and thickness were poorer in the unfed hens from younger flocks, whereas both indices were improved with access to forage for both the young and older flocks (P < 0.05). This study demonstrated that providing access to forage for heritage chickens like the Barred Rock breeds would improve the egg quality, particularly enhancing yolk color and shell characteristics. In conclusion, providing forage access to older flocks may afford significant impacts in retarding egg quality deterioration, with potential for increased consumer preference due to its enrichment of yolk color and eggshell quality.