Development of a life cycle impact assessment methodology for animal welfare with an application in the poultry industry

To date, assessment of animal welfare impacts remains largely unconsidered in life cycle assessment (LCA). Two previous attempts have been made to integrate animal welfare assessment into the LCA framework, both of which are insufficient in their coverage of the numerous factors contributing to animal welfare impacts. Here, a novel type 1 (i.e., reference scale) life cycle impact assessment method is proposed for animal welfare assessment of laying hens. This includes identification of all requisite components of a life cycle impact assessment method (i.e., area of protection, stakeholder and impact categories, impact subcategories, inventory indicators and data requirements, and characterization factors) based on a review of the animal welfare literature, in line with best practices in both the animal welfare science, and life cycle assessment fields. The proposed method is subsequently tested using a case study of the Canadian egg industry, and levels of relative risk for different impact subcategories related to animal biological health, behaviour, and affective state are calculated. This method provides results in line with expectations based on the animal welfare literature. Further, the process used for development of this method is generalizable, and may be applied to development of similar methods for assessment of other livestock species, as the area of protection, stakeholder and impact categories, and impact subcategories are not species specific. This method improves upon previous efforts to incorporate animal welfare assessment into the LCA framework. Continued improvement is necessary however, particularly with respect to incorporation of additional hen life cycle stages, modeling of affective state and positive welfare contributions, and uncertainty assessment. Continued development of animal welfare LCIA methods is necessary given the growing status of animal welfare as an issue of concern worldwide, and to ensure net-positive sustainability outcomes in food systems.