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Detection, causation and potential alleviation of bone damage in laying hens housed in non-cage systems - AW0234

Limited evidence currently available suggests that the prevalence of fractures sustained during the laying period is increasing in the UK flock. Although no representative data exist, observations from particular flocks housed in free-range, single-tier aviary and enriched cage systems, suggests that the prevalence of fractures may have almost doubled over the past 10 years. In many flocks over 60% of birds have sustained a fracture, usually of the keel bone, by the end of lay. The aims of this project are to:(1) provide an accurate assessment of the current levels of old breaks in end-of lay hens and assess how management practices, breed and housing design inter-relate in their association with damage prevalence and severity. It is important to know whether variation currently exists in the UK flock and to identify the most significant risk factors. (2) determine when damage occurs during the normal laying cycle and identify critical time and control points. This will be achieved using a replicated prospective study of flocks housed in indoor barn systems, enabling close observation of behaviour. This part of the study will examine inter-relationships between bird behaviour, changes in management practice that occur during the laying cycle, bone strength and the incidence of fracture. (3) investigate new non-invasive methods of monitoring bone breakage, metabolism and repair. This is important because relevant information about fractures otherwise has to be obtained by full dissection, by imaging methods that are difficult to use in an on-farm situation, or by palpation which still requires considerable bird handling. A valid, non-invasive method would provide a useful audit tool. (4) evaluate intervention aimed at alleviating this welfare problem. This will require an evaluation of the results of objectives 01 and 02 of the project and further consultation with DEFRA. An existing commercial population of birds, receiving dietary supplementation (to provide an altered human dietary intake) will also be examined and compared with birds housed in similar conditions. This research will identify whether variation in fracture rates exists, and will pinpoint risk factors.
Project Documents
• Final Report : Detection, causation and potential alleviation of bone damage in laying hens housed in non-cage systems   (1399k)
Time-Scale and Cost
From: 2004

To: 2008

Cost: £435,592
Contractor / Funded Organisations
University - Bristol
Animal Welfare              
Plants and Animals              
Fields of Study
Animal Welfare