Animal welfare issues related to intestinal health, an essential component in modern chicken production

Animal welfare can be defined as - ‘the physical and mental state of an animal in relation to the conditions in which it lives and dies’. Domestication has occurred very recently in the evolutionary history of poultry, and has barely altered the birds behavioural motivations, despite sometimes great changes in physical appearance and productivity.

Historically, animal welfare was assessed using rather ‘blunt’ indicators including mortality, stocking density and disease incidence. In the last 30 years, metrics such as foot pad dermatitis, size variation, skin conditions, ascites, and rejection of birds at slaughter have been widely collected, particularly at the time of slaughter, and these measures can give ‘basic’ information on the factors affecting bird health and welfare.

In the last 20 years, the effects of ‘subtle factors’ have become more important, as poultry (broilers and ducks in particular) now have the potential to grow, and be productive, at physiologically extraordinary rates. Many subtle ‘impacts’ on bird health and welfare can now be assessed, and to an extent ‘controlled’. These include genetic and physical factors such as skeletal, gut, cardiac and respiratory capacities (influenced greatly by genetics through the breeder companies); behavioural factors such as the impact of enrichments, platforms, capacity to dust bathe, lighting and rest patterns, sound; human animal interactions (stockmanship, animal observation and checking); health and disease factors including the effectiveness of vaccines and biosecurity; and environmental factors including temperature, humidity, air quality, light intensity, duration and wavelength, litter quality. Nutritional factors are also ‘better understood’ - including mycotoxin exposure, intestinal microbiological challenges, microbiota, intestinal immune system competence, and epithelial barrier function. The productive and welfare effects of additives used to promote and maintain gut health, including understanding of the interactions between nutrients including vitamins, prebiotics, and probiotics, organic acids, phytochemicals, enzymes, and trace minerals.

How to make sense of the myriad factors which can influence bird performance and welfare?

One aspect on ‘understanding and control’ is the use of realistic indicators of both performance and welfare, so that impacts of intestinal health on bird health, productivity and welfare can be recognised and optimised. Having the right ‘metrics’ of health and welfare (sensitive enough, but also cost effective and realistic to carry out) is not easy to achieve. High tech monitoring, including precision farming methods (cameras, image analysis, microphones, inline sensors) may seem attractive, but technology does not always sit comfortably in the cost sensitive and physically challenging world of the poultry house. Where ‘doable’ health and welfare monitoring is possible, it is likely to be beneficial to productivity; it may be a useful tool for day to day checking of the bird status; and it could provide the opportunity for the bird to achieve both high productivity, and the best ‘physical and mental state in relation to the conditions in which it lives and dies’.

Presented at the 7th International Conference on Poultry Intestinal Health, Cartagena, Colombia, 2022. For information on the next edition, click here.