Plumage damage (PD) caused by severe feather pecking, skin injuries (SI) caused by cannibalism, and keel bone alterations present major challenges for animal welfare, performance and profitability in commercial pullet rearing and subsequent laying hen management. Preventive measures should already be implemented during rearing, but prospective longitudinal studies during the rearing period investigating how dietary fiber contents and aviary management influence the integument and keel bone condition of pullets are scarce. Therefore, the aim of this study was to investigate the influence of the fiber content in pullet feeds and the timing of aviary opening on integument characteristics and keel bone deviations in pullets of a brown laying strain. A total of 3,872 non-beak-trimmed pullets (Lohmann Brown Classic) were kept in an aviary system with 16 compartments in a 2 × 2 factorial experimental design: Feed with a fiber content typically used under practical rearing conditions (crude fiber: 4.9% in grower, 5.8% in developer) vs. moderate elevated fiber feed (crude fiber: 6.8% in grower, 7.8% in developer) and early (day 14) vs. late (day 28) opening of the aviary levels. In weeks 4, 8, 12 and 16, PD to the back and belly, wing feather loss and SI were scored and the keel bone was palpated. Binary logistic regression models showed significant associations between the dietary fiber content and the time of opening the aviary with PD (P ≤ 0.012) and SI (P ≤ 0.004), but not with wing feather loss (P ≥ 0.685) and keel bone deviations (P ≥ 0.148). Keel bone deviations were detected in 5.4% of birds at week 16. The back/belly plumage and skin showed more damage when the aviary was opened later and the fiber content was lower. For skin injuries, there was a significant interaction between feeding and the time of opening the aviary (P=0.009), as the positive effect of fiber intake was only observed when the aviary was opened at day 28. These results highlight the potential of targeted feeding and environmental strategies during rearing to promote integument health and reduce risk factors for PD and SI.
Schreiter et al. (Mon,) studied this question.