On-farm evaluations of animal welfare indicators in laying hens housed with and without environmental enrichment

In laying hen husbandry, severe feather pecking and cannibalism are multifactorial problems. Solving these problems is a matter of urgency, as beak trimming is banned in several European countries, including Germany. One approach to addressing severe feather pecking and cannibalism is the administration of additional enrichment material to support normal behaviour. In this on-farm study, two flocks of 17,500 Lohmann Brown-Lite laying hens each were evaluated during one production period (18–78 weeks of life, WoL). One flock was provided with alfalfa bales and pecking stones in combination (EnGr), whereas the other flock served as a control without additional enrichment material (CoGr). During production, the flocks were visited at regular intervals. On each visit, a sample of 50 hens per flock were weighed and scored for plumage condition and skin lesions. The mortality rate was recorded daily by the farm staff. No significant difference in plumage condition and mortality rate was found between EnGr and CoGr (p > .05, Mann-Whitney U test). As there were hardly any skin lesions in both groups during the study period, the effect of additional enrichment material on this variable could not be determined. The average body weight of the EnGr was significantly higher than the average body weight of the CoGr on numerous examination days (26 WoL, p < .001; 34 WoL, p = .040; 42 WoL, p = .007; 62 WoL, p = .041; 66 WoL, p = .006; 74 WoL, p = .036; 78 WoL, p = .028, t-tests). However, this effect could not be clearly attributed to the administering of additional enrichment material, as the feeding and performance variables for EnGr and CoGr had been recorded together because of the housing for the two flocks being supplied by one silo and water source, and eggs from the flocks being collected altogether.