Corticosteroids and other indicators of hens' well-being in four laying-house environments.

Abstract

Four presumed criteria of well-being were compared using data from hens of four genetic stocks kept in each of four laying-house environments. Differences between strains selected for increased egg mass and unselected control stocks were not detected, and interactions of selection method with housing environment and periods after housing were not found. Plasma corticosteroid concentrations present during the first 2 weeks after housing were higher than those obtained later. Hens kept in 12-hen, low-density floor pens and 6-hen, high-density cages at 2900 and 310 cm2/hen, respectively, did not differ from each other in corticosteroid levels. However, hens in the floor pens and high-density cages had higher levels than did hens in single-hen, low-density cages and those in 4-hen, moderate-density cages (the latter with floor spaces of 929 and 464 cm2/hen, respectively). Mortality was higher and egg mass per hen housed was less in the 6-hen cages than in floor pens, single-hen cages, and 4-hen cages during the 40-week period following housing. Feather damage and loss increased stepwise and significantly with number of hens per cage. Plasma corticosteroid concentrations did not yield results consistent with other criteria of hens' well-being. There is a need to look beyond the results of corticosteroid assays in establishing hens' well-being in widely different environments.