Behaviour and welfare concepts in laying hens and their association with housing systems

The majority of commercial layers in the world is kept in confined cage housing systems where the birds are unable to exhibit their normal behaviours like dust bathing, perching, foraging and nesting etc. The space requirement in battery cage system is much less than the aviary and free range system. Though cage-free systems provide better welfare, there are issues of cannibalism, fracture, spread of diseases, air quality, egg quality and health of the birds. Worldwide there is diffusion in the welfare regulations for both layers and broilers. There is increasing awareness among consumers regarding the origin of their poultry products and simultaneous need to improve the current level of bird welfare by the egg industry. Thus, welfare concepts not only emphasize five freedoms but also have biological, cultural, economic, social, philosophical, emotional, legal, and political dimensions. The degree of free choices made by well informed and educated consumers may play an important role in implementing welfare measures. There is also a need for additional research on economic implications of welfare under different agro climatic conditions. This review will mostly highlight productivity, behavioural restrictions and welfare issues of laying chickens under different farming systems.