A standardized cage measurement system: A versatile tool for calculating usable cage space1

Abstract

SUMMARY The United Egg Producers husbandry guidelines for cages recommend a minimum of 432 to 555 cm 2 (67 to 86 in. 2 ) of usable space/hen, defined as floor space that is of sufficient height for hens to stand upright. Because there is neither a quantitative value given for cage height nor an established method for calculating usable space, meeting this guideline poses challenges for producers. The objectives of this study were to design a tool that could be used to calculate usable space and evaluate the effect of cage height on that space. Based on some reported hen behavior, it has been suggested that cage height should be at least 35.6 to 40.6 cm (14 to 16 in.), the effect of these height specifications on usable space was assessed. Using cage measurements taken from 180 commercial houses, we found that usable space declined as the specification for cage height increased from 30.5 to 47.0 cm (12 to 18.5 in.), with this decline occurring more rapidly for A-frame than vertical cages. When cage height was set at 35.6 cm (14 in.), almost all houses had cages with usable space. When it was set at 40.6 cm (16 in.), 97.5% of houses with vertical cages and only 30% of houses with A-frame cages had cages with any usable space. Although additional investigation into the effects of cage height on hen productivity and welfare is required to establish a scientifically justified cage height recommendation, this tool will be useful for producers and engineers in determining usable space across a range of hen strain sizes and cage designs.