The Poultry Science Association (PSA) is conducting a study to identify what is known and what is not known about different laying hen production systems, from the point of view of sustainability.

Funded by the American Egg Board, the findings of the study will be presented at a PSA Emerging Issues Symposium: "Social Sustainability of Egg Production". The symposium will summarise an extensive review of academic literature relating to sustainability issues, a great deal of which has been generated in the last decade but which has never before been gathered together systematically for concentrated review under the rubric of sustainability.

The literature review has been conducted by a group of approximately 40 scientists, economists, philosophers, social scientists and other experts, according to Joy Mench, D.Phil., professor and director of the Center for Animal Welfare at the University of California, Davis, and one leaders of the project. For the purposes of the study, sustainability is defined to include issues relating to: hen welfare; environmental issues; egg production economics; worker health and safety; food safety; and public values, attitudes and perceptions relating to egg production.

Dr Mench: "The US egg industry is receiving pressure to change its production practices, particularly as these practices relate to the welfare of laying hens in conventional cage systems. The pressure is particularly acute because of the impending elimination of these conventional cage systems in Europe, beginning in 2012, following an EU vote in 1999 to ban them. In the US, we have begun to see individual states following suit. California's passage of Proposition 2 in 2008, for example, will, as written, effectively outlaw the use of conventional cages in the state beginning January 1, 2015. A similar law was recently passed in Michigan. We believe it is important to understand the broad ramifications of these and future changes – changes that may have an impact on hen welfare, certainly, but that will just as certainly generate ripple effects far beyond that particular issue as well. It is this broad array of potential animal welfare, economic, food safety and other issues that we hope to better understand."

The final goal of the project, according to Dr Mench, is to develop future research priorities, based on the initial literature survey, and then to seek funding to carry out that research. Some of these priorities are already coming into focus.