Review of welfare research in the laying hen and the research and management implications for the Australian egg industry
Authors: Barnett J. L. , Newman E. A. 
Published: August 2004

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.