Are slow-growing broiler chickens actually better for animal welfare? Shining light on a poultry welfare concern using a farm-scale economic model.

1. It remains unclear whether slow-growing broilers actually represent an overall animal welfare improvement - a major knowledge gap for policymakers and animal welfare NGOs. This paper addresses this knowledge gap by using an economic model to produce an all-things-considered estimate of the welfare effects of slow-growing genotypes. A quantitative end-point welfare metric that accounts for welfare challenges throughout the production cycle used the Pain-Track method from the Cumulative Pain Framework.2. Longer lifespans of slow-growing broilers (relative to fast-growing broilers) typically caused an increase in the time spent in low-intensity negative affective states. However, despite the additional broilers being farmed and their longer growth period, switching to slow-growing genotypes caused a decrease in higher-intensity negative affective states - a major win for welfare.3. These results can be used to alleviate consumer and producer concerns that any transition causes a welfare risk and provide an optimistic understanding of the overall welfare impact of transitioning to slow-growing broilers.