Factors associated with variation in laying hen mortality and methods of improving on-farm recording

A Scrase, Sarah Lambton, Claire Weeks

Research output: Contribution to conferenceConference Posterpeer-review


Cumulative mortality data from over 2,000 farms and 3,564 flocks were used to determine the principal factors affecting the recorded levels of mortality. The ten data sources included both health and welfare monitoring bodies and previously published scientific studies mainly from UK farms with one from the Netherlands and Sweden. Average flock size was 11,742 hens with a range: 6-172,500.
The overall mean level of mortality from the dataset was 7.9% with a standard deviation of 7.1 reflecting high variability, as also indicated by the very wide range of losses between flocks of 0 to 69.3%. Data were collected between 16-208 weeks, with a mean age of 65 weeks; 75% of data points were from flocks 60 - 100 weeks of age. Apart from an expected significant increase with age, other factors significantly (p<0.001) associated with cumulative mortality in statistical models of the data were higher levels in flocks of intact beaked birds and differences between housing system and breeds. 
Mortality is a bird-based indicator of welfare that has the potential to be objective and accurate. As such it is increasingly included as part of assurance assessment as well as being used in scientific evaluations of welfare. However, we have found that farmers can find it difficult in practice to keep easily accessed records of mortality. We therefore conducted telephone interviews with farmers to determine their current methods of recording mortality and their ‘wish-list’ for improvements. We also developed an App to record mortality directly onto a mobile phone as ‘found dead’ or ‘culled’ with opportunities to ascribe the causes of death in broad categories such as disease, pecking injury, smothering and predation. The App was distributed to nine UK farms for a four month trial period. In post-trial interviews, 78% of participants reported recording more detail into the app than their current paperwork systems. Having access to graphical summaries of electronic data and more information on causes of mortality had several benefits for farmers, most notably in aiding flock health management decisions. This trial indicated the potential for app technology to be used on farm to collect more detailed mortality data, whilst also aiding farm management processes.
Reducing overall levels of mortality would benefit not only bird welfare but the profitability and sustainability of egg production.
Original languageEnglish
Publication statusPublished - 2014
EventRecent advances in animal welfare science IV: UFAW Animal Welfare Conference - York Merchant Adventurers’ Hall, York, United Kingdom
Duration: 26 Jun 2014 → …


ConferenceRecent advances in animal welfare science IV: UFAW Animal Welfare Conference
Country/TerritoryUnited Kingdom
Period26/06/14 → …


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