a1 Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Funbo-Lövsta Research Centre, 755 97 Uppsala, Sweden, e-mail: firstname.lastname@example.org
A review is presented of results from research and commercial production of two alternative keeping systems – furnished cages and aviary systems. These systems have gradually evolved through criticism of conventional cage keeping of layers, mainly in North Western Europe, due to the lack of possibilities for birds to perform natural behaviours and to restricted space. They provide birds with nests to lay eggs in, perches to rest on, and litter material to manipulate and dust-bathe in. Experience and development of the aviary are longer than that of furnished cages, the latter existing in wide spread commercial production only in Sweden as yet. However, according to a new EU-directive in 1999, conventional cages may not be used as a new investment from 2003 and not at all from 2012. Birds in both systems may produce well but the aviaries are less predictable due to irregular outbreaks of flock cannibalism, especially in non beak-trimmed medium heavy brown birds, despite offering the birds litter and plenty of space. The furnished cages try to combine advantages of small group size in cages and reduce disadvantages of poor air condition, and sometimes inferior hygiene, in floor-kept hens. They are still subjected to extensive improvements in details of design e.g. to enhance egg quality. Hence, results may vary considerably between models. In order to maintain a stable social order it is probably vital to retain a moderate group size in furnished cages.