The assessment of plumage and integument condition in laying hens provides useful information about the occurrence of feather pecking and cannibalism. Although feather loss and skin injuries can result from mechanical abrasion or clinical diseases, they are valid animal-based indicators for behavioural disorders. This particularly applies to damage on the back and tail region of the hens. The aim was to evaluate the behaviour of dual-purpose breeds (Lohmann Dual, LD) and conventional layer hybrids (Lohmann Brown plus, LB+), and to compare a mere visual assessment (Visual Scoring, VSc), with a method involving the handling of individual animals (Hands-on Scoring, HSc). During weekly VSc, the hens' plumage and integument were scored on five body parts. HSc was carried out on seven study days applying the same scoring scale as for VSc. In LB+ hens, minor plumage damage started at 25 weeks and increased to the 71st week. With 99.5% of LB+ showing feather loss to a different extent, the back was the most severely affected body part. In contrast, only between 4.5% and 7% of LD showed minor feather loss at the end of the study. Integument damage reached a peak, with 6% affected LB+ in week 66. Injuries were found only sporadically in LD hens. Spearman's rho for the comparison of plumages scores given in VSc and HSc was >0.90 (p < 0.01) in both hybrids for most of the tested body regions and weeks, except for the breast/belly region. However, VSc and HSc were equally valid for detecting skin injuries of all of the body regions (rs > 0.86, p < 0.01). Damaging behaviour only occurred in the LB+ flocks, though both of the genetic strains were kept under the same conditions. The visual scoring method was suitable for detecting both plumage and integument damage.
Keywords: animal welfare; cannibalism; feather pecking; laying hens; on-farm assessment.