[Enriched cage systems for laying hens--legal minimum conditions and starting points for their scientific evaluation]

Recent developments in the European and national legislation regarding minimum standards for the keeping of laying hens will be causing changed conditions for egg production in the medium term. Enriched cages shall allow hens to better fulfill their needs than traditional battery cages. More space for the stretching of wings and legs, perches for resting, littered areas for scratching, pecking and dustbathing and nests for egg-laying behaviour shall allow layers to perform more of their normal behaviour patterns. However, regarding the sustainability of these systems there are different views and still a great lack of scientific data and practical experience. An overview is given on the development of European and national animal welfare legislation concerning laying hens, minimum requirements for enriched cages and the available evidence about animal behaviour, performance and health in these systems. Furthermore, a current project at the School of Veterinary Medicine Hannover on the animal welfare assessment of enriched cages, specifically on the Aviplus cage system, which was one of the first systems on the market and is in accordance with EU-directive, is introduced.