Laying Performance and Fear Response of White Leghorns as Influenced by Floor Space Allowance and Group Size

Abstract

Three experiments were conducted with White Leghorn pullets housed in litter-floored pens to determine the effects of floor space allowance and group size on laying performance and fear response. In Experiment 1, 17 birds were housed at a floor space allowance of .40 or .29 m2/bird. In Experiment 2, 22 or 16 birds were housed at a floor space allowance of .31 m2/bird. The following treatments were used in Experiment 3: 1) 26 birds per pen at. 19 m2/bird, 2) 36 birds per pen at. 19 m2/bird, and 3) 26 birds per pen at .26 m2/bird. The test period was from 20 to 52 wk of age in each experiment. Duration of the induced tonic immobility, measured at 52 wk of age, was used as a criterion of fearfulness.Decreasing floor space allowance per bird, increasing group size per pen or a combination of the two had no significant effect on final body weight, hen-day egg production, feed efficiency, egg weight, albumen height, or fearfulness of the bird. Decreasing floor space per bird while holding the number of birds per pen constant significantly (P<.05) increased mortality. Birds given less floor space consumed significantly (P<.05) more feed than birds given more floor space in Experiment 1. This study indicates that the birds' hen-day egg production, feed efficiency, and fearfulness are not significantly (P>.05) influenced by floor space allowance or group size and that effects of floor space allowance and those of group size are not additive.