Effects of edible environmental enrichments during the rearing and laying periods in a littered aviary – Part 1: Integument condition in pullets and laying hens

ABSTRACT Severe feather pecking is a damaging allopecking behavior in pullets and laying hens that was found to be associated with multiple factors (i.e. genetics, husbandry, nutrition). The aim of this study was to investigate whether the occurrence of feather pecking could be reduced by additional environmental enrichment materials (EM; pecking stones and hard-pressed alfalfa bales) in a littered housing system. In total 4,000 pullets were reared in a 16-compartment aviary system until week 18, and 1,320 remaining laying hens were kept thereafter, from week 19 to 48, in 44 compartments. During the rearing period, half of the compartments were permanently supplied with enrichment materials, while the other half (control groups) did not receive any EM. In each of the two variants, 1,000 brown-egg layer hens of the genetic strain Lohmann Brown classic (LB) and 1,000 white-egg layer hens of the strain Lohmann Selected Leghorn classic (LSL) were reared. After transferring to the laying hens’ stable, we examined the LB and LSL hens under four treatment variants: : V1 - no EM over the entire study period (LB: n=150, LSL: n=180); V2 - rearing period with and laying period without EM (LB: n=180, LSL: n=150); V3 - rearing period without and laying period with EM (LB: n=180, LSL: n=150); V4 - EM over the entire study period (LB: n=150, LSL: n=180). The integument condition (i.e. beak protrusion, beak fissures, plumage condition, skin and toe injuries, and foot pad dermatitis) was scored in weeks 2, 4, 6, 10, 14, 18 (rearing period) and 25, 30, 40, and 48 (laying period). EM provision resulted in less plumage damage and skin injuries (p≤0.05). On combined evaluation of the two strains, significant differences were observed with V4, which had less severe feather damage in week 30 compared to the three other variants (p