Health and production in improved cage designs.

This paper describes the effects of various cage designs on health characteristics such as skeleton strength, plumage and foot condition, mortality, and some production traits such as egg quality and feed consumption. Three major steps in improving cage design and in developing new cage designs are described. Firstly, cage design in general has been improved by comparing different conventional commercial cage designs under the same experimental conditions. Secondly, unconventional design features, such as an abrasive strip to reduce excessive growth of claws or a perch to improve the behavioral repertoire for the hens as well as to strengthen skeletal structure, are described. Thirdly, the effects of fully furnished cages that also include a nest and dustbath for smaller or larger groups of birds are discussed. These designs create an environment in which the problems of conventional cages, such as behavioral restriction, are reduced and the shortcomings of large litter aviaries, such as cannibalism, parasites, and a poor working environment, are improved. Cages with one perch level containing groups of 4 to 10 hens seem more likely alternatives to conventional cages on larger scale farms than litter systems or colony cages for more than 10 birds. This is due mainly to the higher predictability of production, the decreased risk of cannibalism, and improved hygienic conditions.