The effect of hay bales and perches as environmental enrichment material was investigated on the behavior, heterophil/lymphocyte (H/L) ratio, footpad dermatitis (FPD), and productivity of Japanese broilers in a commercial farm. About 21,500 birds were allocated to 4 houses: male versus female×control versus treatment house. We observed maintenance behavior, the utilization of hay bales and perches, and the H/L ratio of birds at 3, 5, and 8 weeks of age. FPD was scored and productivity was calculated at about 60 days after hatching. Compared to birds in the control houses, birds in the treatment houses invested more time in stand-resting and moving behaviors (P＜0.01, for each behavior) and less time feeding, drinking, and sit-resting (P＜0.01, for each behavior). Females used the hay bales and perches more than the males (P＜0.1 and P＜0.01, respectively). The activity and utilization of hay bales and perches decreased with age (P＜0.01, for each behavior, respectively). The H/L ratio of birds in the treatment houses was lower than that in the control houses (P＜0.01). The prevalence of FPD was milder in the treatment houses compared to the control houses for females (P＜0.01), but not for males. In conclusion, hay bales and perches represent effective enrichment materials, allowing broilers to express normal behavior, alleviating stress in the younger and lighter birds of both sexes, and reducing FPD in female birds using the hay bales and perches more than males.

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