Evaluation of colony size and cage space for laying hens (Gallus domesticus) using fuzzy decision analysis

A replicated experiment (two, 1-yr trials) was conducted to define colony size and cage space requirements of laying hens. DeKalb XL pullets, 19 wk of age, were randomly assigned to cages sized 1548, 3097, and 4645 cm2 at population densities of 2, 3, 4, or 5 hens. Membership values for fuzzy decision analysis were related to the performance of birds as measured by hen-day production and cumulative mortality. The decision analysis showed the crossover point between an uncrowded and a crowded condition was 3 birds in both trials for cage sizes of 1548 and 3097 cm2 based on maximin [corrected] decision values. The crossover point for the largest cage area (4645 cm2) differed between 3 and 4 birds for Trials 2 and 1, respectively. This suggested crowding pressure was not as great when more space was available to the birds.