Dr. Peter Holt will publish a white paper in an upcoming edition of Poultry Science entitled “The Impact of Different Housing Systems on Egg Safety and Quality.” Co-authors include Dr. R. H. Davies, of the Veterinary Laboratory Agency Weybridge in the UK; Dr. J. Dewulf, of the University of Ghent in Belgium; Dr. Richard Gast, of the USDA-ARS- SEPRL; Dr. D.R. Jones, of the USDA Egg Safety and Quality Research Unit; Dr. Douglas Waltman, of the Georgia Poultry Laboratory; and Dr. K.L. Willian, of Tuskegee University.

The survey data on the prevalence of SE appears contradictory and inconsistent with differences between results obtained in Europe and the U.S. As previously noted in Egg Industry, adherence to effective egg quality assurance programs and the adoption of vaccination can markedly influence the recovery of SE from the environment of flocks and eggs. The authors concluded that there is no general consensus demonstrating the superiority of one housing system over another with respect to either food safety or quality.


Although minor differences in nutrient content of eggs may be recorded, comparisons between conventionally caged and free-range hens are obscured by lack of details concerning compositions of diets fed to hens which were surveyed. It is known that omega-3 fatty acid content, vitamins A, D and E can be enhanced by appropriate dietary supplementation. With respect to safety, contamination with chemicals and pesticides may be a problem with eggs derived from hens allowed free access to the outside of barns.

The authors concluded, “Many factors besides housing type affect the safety and quality of eggs. These effects need to be taken into account before conclusions can be made regarding the efficacy of different housing systems in relation to egg safety and quality.” The Holt et al. article will not resolve any ongoing debate between the opponents of confined housing and the industry.