Effect of pecking stones and age on feather cover, hen mortality, and performance in free-range laying hens.

Severe feather pecking is frequently associated with impaired egg production, poor hen welfare, and increased mortality. The aim of this study was to investigate the potential of pecking stones to ameliorate the incidence of feather pecking. A total of 18 flocks of Hy-Line Brown laying hens were randomly assigned to control (n = 9 no pecking stone access) or treatment (n = 9 pecking stone access) flocks and housed in commercial fixed sheds (farm A, n = 10) or commercial mobile sheds (farm B, n = 8) differing in various housing conditions. Beak length, feather score, egg production, and mortality were evaluated at 16 wk of age and every 10 wk until at least 46 wk of age. On farm A, hens with access to pecking stones had significantly lower mortality than hens without pecking stone access (P = 0.001). A significant interaction between pecking stone and age was observed on feather scores of wings of hens housed in farm A. Hens of the pecking stone group in farm A had higher wing feather score (indicating better feather condition) at the age of 56 and 66 wk than hens with no access to pecking stones (pecking stone × age, P = 0.002). The age of the hens was significantly associated with lower overall feather scores (poorer feather condition), reduced egg production, and higher mortality (P < 0.05). Although pecking stones reduced some feather loss and mortality, this effect was only present on one farm and therefore may be related to farm management. Especially the impact of pecking stones on mortality was inconclusive as the cumulative mortality in farm B was nearly twice as high compared with that in control flocks. Further investigations are warranted including the effects of pecking stone provision at an early age such as during rearing (0-17 wk of age).