Behavior and welfare of laying hens and broiler chickens

Although broiler chickens and laying hens belong to the same species, Gallus gallus domesticus, differences in genetic selection pressures, typical housing systems, and age at slaughter result in unique welfare issues (Brunberg et al., 2011, Lay et al., 2011). For example, broiler chickens are at risk of ascites and leg diso rders associated with their rapid growth (Hepworth et al., 2011; Lister et al., 2010), whereas laying hens can be challenged by osteoporosis and cannibalism (Yngvesson et al., 2004). Chicken welfare depends not only on physical health but on psychological health as well. The latter is more difficult to evaluate but vocalizations, behavioral postures, motivational strength, cognitive bias, and self-administration of analgesics can provide indirect measures of psychological welfare (Savory y Hughes 2010, Newberry et al., 2007). One of the most controversial topics requiring attention is acceptable space allowance for poultry (Thogerson et al., 2010). Determining acceptable methods for slaughter (Shields and Raj 2010) and to mass euthanasia of poultry with reportable diseases such as avian influenza is an emerging issue. The purpose of the conference is to outline poultry welfare goals, to identify important welfare issues in broiler chickens and laying hens, and to discuss welfare assessment (Shimmura et al., 2011). Solutions to welfare challenges are addressed, with an emphasis on environmental enrichment (Newberry 1995) and development of welfare assurance programs.