Research undertaken by a commercial farm and an educational institution has discovered that slow growers are healthier compared with fast ones.
FAI Farms and the University of Bristol and the Norwegian University of Life Sciences, investigated a comprehensive suite of positive and negative welfare indicators in 4 production systems, varying in stocking density and breed.
A group of the slower-growing breed were stocked at a planned maximum density of 30kg/square metre; the second group of slower-growing breed at 30 and 34kg/square metre and the welfare outcomes were compared to those of a standard fast-growing breed stocked at 34kg/square metre.
At the lower density, the slowest growing breed was found to have slightly better welfare, with lower mortality.
Slowest growing breed recorded better welfare
At the lower density, the slowest growing breed was found to have slightly better welfare than the other slower growing breeds – indicated through lower mortality, fewer rejections at processing and better walking ability. Differences in welfare of the slower growing breed stocked at 2 densities were small.
…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 slower growing flocks.”
However, prominent differences were found between the standard fast-growing birds stocked at 34kg/square metre and birds in the 3 other systems. The standard birds experienced poorer health as indicated by higher levels of mortality, hock burn and pododermatitis as well as greater rejections at processing. The conventional birds showed less perching on enrichment bales as well as fewer positive play and exploration behaviours.
Lower density is good but slower growing is better
The results showed broiler breeds with faster growth rates had lower activity levels, poorer indicators of mobility, poorer foot and hock health, higher biochemical markers of muscle damage and potentially inadequate organ development.
The authors of the latest study, published in Scientific Reports, said that while there are benefits of providing birds with more space, by slightly reducing animal density, changing to a slower growing breed resulted in much better health and more positive experiences for the broilers.
Robust evidence of health & welfare benefits of slower growing breeds
The independent commercial scale trial provides robust evidence of the health and welfare benefits of slower growing breeds of chicken. Research hopes it will help drive changes in supply chains and large companies to bring about real improvements to chicken welfare.
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.
The study found slow growing birds to have better health and perform more positive behaviours than conventional fast growing broilers.