Life cycle assessment of contemporary Canadian egg production systems during the transition from conventional cage to alternative housing systems: Update and analysis of trends and conditions

Abstract The supply-managed Canadian egg industry produces over 789 million dozen eggs per year, the majority of which are produced in conventional cages (∼60%). Recently, the industry committed to a complete transition to alternative (i.e. enriched cage, single- and multi-tier free run, free range, and organic) production systems by 2036. This transition may have significant sustainability implications. Here, we present updated (i.e. based on 2019 data) LCA models and results representing the cradle to farm gate environmental impacts of Canadian egg production systems based on a much expanded data set compared to previous models. Generally, input and emission levels decreased across all housing systems, with few exceptions, compared to previously reported levels. Acidifying and GHG emissions decreased across most housing systems due to increases in feed- and pullet-use efficiency, while eutrophying emissions increased across all housing systems modeled due to differences in manure management systems. Feed inputs represented the greatest contributor to most impact categories (∼18% - 84%), followed by pullet production and manure management (∼ 10% - 37% and ∼0.01% - 62%, respectively). Organic production systems had the lowest impacts in nine of the ten categories assessed, while free range systems generally performed the worst. Conventional cages generally had lower impacts than all non-organic systems. However, it can be expected that as farmers gain experience with alternative systems resource-use efficiency levels will increase and environmental impacts will decrease. Continued monitoring of environmental performance of Canadian egg production systems is therefore imperative to ensure net-positive outcomes during this housing system transition.