Behaviour problems associated with selection for increased production.

Some management practices, such as beak trimming and very low light intensities, have masked some of the behavioural problems caused by selection for higher production capacity. Because of animal welfare concerns and the growing markets for eggs and meat produced in alternative production systems, production practices are again changing rapidly and behavioural problems are reappearing. The more important of these behavioural problems in laying hens, as well as the major welfare issues associated with selection of meat-type birds for rapid growth (such as skeletal disorders and the severe feed restriction imposed on broiler breeders) are discussed.