Pecking and piling: The behaviour of conventional layer hybrids and dualpurpose hens in the nest

Oviposition in an appropriate nest is a behavioural priority in laying hens, and layer strains are known to differ in their patterns of nest use. However, besides oviposition, laying hens often show undesired behaviours such as aggression or gregarious nesting in colony nest boxes. The aim of the present study was to obtain basic information on the patterns of nest use and the behaviour in the nest of dual-purpose hens (Lohmann Dual, LD) by comparing them to a conventional layer strain (Lohmann Brown plus, LB+). In addition, the effect of nest location was tested for each hybrid. About 1850 untrimmed hens per genetic strain were housed in four compartments of an aviary system with colony nest boxes on the top tier. Video-based data were recorded in the first (N1) and the sixth nest (N2) in a row of nest boxes in each compartment at three times during the laying period to assess the number of hens per nest, the duration of nest visits of focal animals, and the behaviour of the hens in the nest. In general, a larger number of LD (0.87 ± 0.09–10.63 ± 0.30) than LB+ hens (0.21 ± 0.04–4.90 ± 0.24) was observed per nest box. In both hybrids, more hens were found in N1 compared to N2 (P < 0.05). Except for 43rd–48th weeks of life, the durations of nest visits did not differ between LB+ (09:51 ± 00:41–18:25 ± 00:48 mm:ss) and LD hens (07:14 ± 00:32–17:14 ± 00:32 mm:ss). However, both hybrids spent more time in N2 compared to N1 (P < 0.05). Hybrid effects (P < 0.05) were found for nearly all of the observed behaviours. In particular, LB+ hens performed more total pecking behaviour, whereas LD hens showed more piling in the nest. In the LB+ hens, nest location affected only few of the behaviours. In contrast, nest location effects were found for most of the behaviours observed in the LD hens. Particularly piling occurred to a larger extent in N1. The present results indicate that the patterns of nest use and the behaviour in the nest differed between conventional layers and dual-purpose hens. Within genetic strain, dual-purpose hens seemed to be more affected by nest location than conventional layers