Effects of environmental enrichments applied to pasture areas on free-range laying hens: 1. Performance and egg quality

This study assessed the effects of environmental range enrichments, bird age and their interactions on laying performance and egg quality from Lohmann Brown hens.2. In total, 900 hens (25 weeks old) were randomly divided into three groups (control, object [OE] and tree [TE] enrichment) with three pen replicates each (100 hens/pen). Each pen was a closed shelter with pasture access nearby. Variously rectangular, square, cylindrical and triangle shaped, red, orange and yellow-coloured boxes, pipes, buckets and structures were used for the OE group, whereas tall and broad-leaved plants and Thuja trees were used for the tree enrichment group.3. Laying performance and egg quality traits were measured at 25–32, 33–40, 41–48 and 49–56 weeks of age.4. Significant differences in egg production were found amongst all groups (p < 0.01) due to differences in mortality at the start of the experimental period (p <<0.001). There were no significant differences between treatments in hen-day egg production. Environmental enrichment significantly decreased the albumen index and affected dirty egg ratio, shell thickness (p < 0.01) and shell weight (p < 0.05). Shell weight showed an interaction between enrichment and age (p < 0.01).5. Age had a significant effect on all performance and egg quality traits (p < 0.05), with 48-week-old hens generating the highest egg mass and hen-day and hen-housed egg production levels (p < 0.01).6. Although environmental enrichment can potentially increase egg production slightly, TE and OE resulted in fewer clean eggs. However, positive effects on albumen and shell quality traits were evident in the OE group.