Review of welfare research in the laying hen and the research and management implications for the Australian egg industry

Abstract

The scientific literature and research in progress since 1992 on poultry welfare were reviewed under the major headings of housing, management, health, and occupational health and safety. Throughout the review there are a number of recommendations for research and implications for the Australian egg industry arising from the current worldwide research. The main recommendations can be summarised as follows. Further economic analyses of perches in cages under Australian conditions are required if the welfare advantages of incorporating perches into cages are to be maximised by the Australian industry. To reduce bone breakage, depopulation should involve removing birds by both legs, and current research on dietary manipulation could lead to a reduction in the incidence of osteoporosis. Injuries and entrapment can be reduced by the application of an abrasive strip to limit claw length, and a simple way of reducing mortalities may be by using coloured plastic enrichment devices. If enriched modified cages are to be adopted, a survey of public attitudes on their acceptability and trialing them under Australian conditions are required. It is important that welfare recommendations from overseas research and development are validated under Australian conditions to prevent compromising bird welfare. Replicated experiments on the welfare implications of non-cage systems are urgently required. Beak trimming remains controversial, and determining the extent of single and double beak trimming and the reasons for their practice may lead to a reduced frequency of use. If beak trimming were to be disallowed in the future, the overseas knowledge on low light levels to reduce cannibalism and intermittent light schedules to maintain production would have to be reviewed, perhaps developed, and adopted. Also, a current common housing option of open-fronted sheds and exposure of hens to ambient light would have to be reassessed. While moulting via dietary restriction is not currently considered a significant welfare issue in Australia, a more sophisticated research approach to manipulate ovarian function that does not rely on food restriction should be researched. Cooling birds by providing cool water or cool radiators may be beneficial to welfare in hot weather. The slaughter process involves a number of potential welfare issues, such as heat-related problems during transport, stunning currents, and gas stunning, that require either a survey to identify problems or assessment. The human–animal relationship probably has an important role in poultry welfare. However, the current understanding of the human factors that regulate human–animal interactions in poultry is poor. Some basic research and considerable applied research are required in this area before it would be possible to benefit bird welfare. Flock health monitoring must be considered as an ongoing priority because of its impact on bird welfare. In the area of health and welfare, the interactions between diet and skeletal condition, disease resistance and transmission, and housing and handling and immunosuppression require further research. Any relevant improvements in technology that arise from overseas research in non-cage environments to improve working conditions should be assessed and, if appropriate, adopted by the Australian industry because of its potential impact on occupational health and safety, work ethic, and the implications this has for bird welfare.