After the ban on conventional cages that will be enforced in 2012 nearly all Norwegian egg laying hens will be reared in aviaries and then housed in aviaries or furnished cages during the laying period. Producers already using these housing systems interm ittently report serious problems with fearfulness, stress, feather pecking and feather loss, and inadequate use of resources. Fear may cause panic reactions and death by suffocation when birds pile up on one another. Stress is associated with inhibition o f growth, a compromised immune system, and decreased productivity. Inadequate use of resources (feed, water, perches, and nest boxes) results in increased mortality and floor eggs. Feather pecking and feather loss reduce feed conversion and may progress t o cannibalism. These problems have a larger impact in aviaries and furnished cages than in conventional cages because of the greater number of animals involved, and the costs to animal welfare and the producers' economy can be substantial. There is no nat ional poultry breeding program in Norway and beak trimming is prohibited. It is therefore essential to develop practical methods of improving welfare and productivity by optimizing rearing methods and management routines. This is the main goal of the prop osed project. The basic research in this project aims at producing new knowledge to help understand how rearing conditions influence cognitive, emotional and physiological development in laying hens. Close collaboration with the poultry industry and large scale studies at conventional farms will ensure the relevance of this research. Knowledge gained through the project will be actively shared with industry representatives and producers and will aim at facilitating a smoother transition from conventional cages to aviaries and furnished cages, thereby contributing to ensuring the welfare of laying hens in future housing systems and the competitiveness of Norwegian egg producers.