Poultry and egg producers have known for a long time that the amount of space a bird is provided, whether in a cage or in a floor system, has an impact on bird performance, whether the measurement is growth rate, egg production or livability. For decades, producers have made a trade-off between bird performance and the cost of providing space to the birds. Broiler and turkey producers reduce downtime between flocks and increase the number of birds in a house when margins are strong, and spread out placements and reduce flock size when margins are poor.
There was a time not that long ago that the No. 1 welfare argument given for confinement housing was the improved bird performance and flock livability when birds are confined versus raised free range. Researchers have worked to establish physiological and behavioral measurements that can be related to bird welfare, but bird performance data is still a piece in the puzzle when evaluating the welfare impact of various housing systems.
A preliminary report on research conducted at Michigan State University evaluating the impact of housing density in enriched colony cages on bird welfare (see Egg output higher in lower density enriched colonies in this issue) finds that white hens housed at 116 and 144 square inches per bird had slightly higher egg production than did the hens housed at higher densities.
This is just one study and more research will be done in this area, but I thought the positive impact of more space on egg output was interesting. Suppose housing densities of 116 square inches per bird or greater do consistently yield better egg output per hen. Does this mean animal welfare groups will accept egg production as a measure of bird welfare and use this as justification for housing densities in enriched colonies to be 116 square inches per bird or more?