Towards a net-zero greenhouse gas emission egg industry: A review of relevant mitigation technologies and strategies, current emission reduction potential, and future research needs

Despite having relatively low greenhouse gas (GHG) emissions compared to other terrestrial animal protein sources, egg production is among the fastest-growing livestock sectors and hence faces mounting pressure to reduce potential climate impacts. This includes both regulatory and market-based initiatives, as evidenced by the increasing number of private and public sector actors adopting a formal net-zero emissions objective. The current review identifies available technologies and management strategies for reducing GHG emissions in the industrial egg sector, taking into account both environmental and technical feasibility criteria. GHG emission reduction potentials for market-ready options are identified and used to derive an overall GHG emission reduction potential estimation for the sector based on the Greenhouse Gas Protocol's three emission scopes and drawing, in particular, on recent research of the Canadian egg industry. Priority research areas to support continued emissions reduction are identified. Widespread implementation of market-ready options could reduce Scope 1 and 2 emissions to zero in the short to medium term. Scope 3 emissions could be reduced between 23 and 95% without offsetting. Important areas for further research include the evaluation of options related to feed production (i.e. conservation tillage and the use of NIs and UIs), least environmental cost feed formulation and feed delivery (i.e. precision feeding for individual birds), as well as potential pathways for carbon sequestration in the egg industry (e.g. via manure pyrolysis) to offset residual emissions.