21 Sept 2020
Slower-growing broiler chickens also have more fun, according to evidence from an independent commercial‑scale farm trial involving the University of Bristol Veterinary School.
James Westgate
Job Title
Choosing slower‑growing chicken breeds is likely to have more impact on animal health than lower-density production or increased space.
Slower-growing broiler chickens also have more fun than conventional breeds of birds, according to evidence from an independent commercial‑scale farm trial involving the University of Bristol Veterinary School.
Carried out by researchers from FAI Farms, the University of Bristol and Norwegian University of Life Sciences, the study has been published in Scientific Reports, and is the first to highlight the welfare differences between fast and slower‑growing broilers in a commercial setting, using a comprehensive suite of positive and negative welfare indicators. It showed that, while providing chickens with space had benefits, by slightly lowering the animal density, changing to a slower‑growing breed resulted in much better health and more positive experiences for these birds.
Annie Rayner, FAI Farms’ lead researcher, said: “Broilers are motivated to perform a range of positive behaviours. These positive behaviours create positive experiences, resulting in enjoyment or pleasure. Displaying positive behaviours improves an animal’s quality of life.
“Our seminal study found slow‑growing birds to have better health and perform more positive behaviours than conventional fast-growing broilers. A shift from fast-growing breeds would provide the most significant improvement for the lives of the 142 million chickens produced in Europe every week.”
Siobhan Mullan, senior research fellow in animal welfare at the University of Bristol Veterinary School, added: “This first independent commercial-scale trial provides robust evidence of the health and welfare benefits of slower‑growing breeds of chicken. We hope it will help to drive changes in supply chains and large companies to bring about real improvements to chicken welfare.”
The NGO-backed European Chicken Commitment (ECC) has attracted widespread attention from commercial broiler production, with several major brands already having signed up – including KFC, Nestlé, Marks and Spencer, and Nando’s.
This study set out to interrogate the commercial welfare implications of two critical aspects of the commitment – a move to slower-growing breeds and lowering the stocking density. The commercial-scale farm trial explored positive and negative welfare indicators in four production systems varying in stocking density and breed.
At the lower density, the slowest‑growing breed was found to have slightly better welfare than the other slower‑growing breed – as indicated by lower mortality, fewer rejections at processing and better walking ability.
Differences in welfare of the slower‑growing breed stocked at two densities were small. However, prominent differences were found between the standard fast-growing birds stocked at 34kg/m2 and birds in the three other systems.
The standard birds experienced poorer health, indicated by higher levels of mortality, hock burn and pododermatitis, as well as greater rejections at processing. Furthermore, the conventional birds showed less perching on enrichment bales, as well as fewer positive “play” and “exploration” behaviours.
Ruth Newberry and Judit Vas, of the Norwegian University of Life Sciences Faculty of Biosciences, pointed to the importance of including indicators of positive experiences in animal welfare studies: “Until recently, play was hardly ever mentioned in studies of chickens.
“We found that, when you walk through a commercial flock, you just have to turn around and look behind you to see chickens frolicking in your footsteps. This was especially the case in the slower‑growing flocks.”
