Extensive study to examine egg-laying hen housing

Collaborators include universities, companies, not-for-profit organizations, and federal government
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A multiyear study involving tens of thousands of egg-laying hens could improve understanding of the impacts and sustainability of housing systems for egg-laying hens.

Michigan State University and the University of California-Davis are leading the study, and officials with McDonald's and Cargill said their companies will serve as contributors and advisers.


Jeffrey D. Armstrong, PhD, dean of the Michigan State University College of Agriculture and Natural Resources, told the AVMA news staff that the study is needed because of the many unanswered questions regarding optimal methods for housing egg-laying hens.

Important considerations when selecting or modifying a housing system, Dr. Armstrong said, are that changing one aspect of production typically results in multiple additional changes, and that hen housing has diverse impacts beyond the welfare of the hens—including impacts on food safety, human health, and the cost of food.

"All of these different factors come into play, and there are very few, if any, studies to look at production like this, in a holistic manner," Dr. Armstrong said.

The AVMA will participate in the study in an advisory role, according to Dr. Gail C. Golab, director of the AVMA Animal Welfare Division. The AVMA has previously provided comments on proposals and grant requests connected with the project, she said.

Other advisers are the American Humane Association, the Department of Agriculture's Agricultural Research Service, and the not-for-profit Center for Food Integrity.

Tim Amlaw, director of farm animal programs for the AHA, said his organization has made footage from daily video monitoring taken during a separate ongoing study on behavior of hens available for the project. That parallel study is being sponsored by the AHA and conducted by researchers from the University of Maryland and Mississippi State University.

The AHA will also allow access to audit data related to humane care from observation and certification programs and will provide any guidance needed on animal welfare during the Michigan State and UC-Davis project, Amlaw said.

It is important to examine humane care practices in food production and deficiencies in those practices, Amlaw said.

"What we're trying to avoid is precipitous change that doesn't result in improved animal welfare," Amlaw said. "So what we want to do is make sure the change is science-based, it observes all aspects of the animal environment, and it looks toward a production system that is fluid and robust for systems of agriculture as we know it."

Dr. Golab said the AVMA's Animal Welfare Division has advocated for research that takes a comprehensive approach toward studying animal welfare, and the design of this project will likely have applicability to animal welfare questions in other species. With respect to laying hens, she said the project should provide insight into the impacts of housing choices not only on the welfare of the birds, but also on the environment, food safety, biosecurity, and supply chain economics.

Three eggs

As for what producers should consider in adopting a hen housing system, Dr. Golab said, "It needs to be animal welfare-friendly across multiple parameters, it has to result in a product that's safe for human consumption, it has to be environmentally responsible, it needs to be viable for adoption by producers, and it must be acceptable to consumers."

Sandy Miller Hays, spokeswoman for USDA's Agricultural Research Service, said an ARS food technologist will serve as a consultant, and her agency will play a minor role in the research.

Terry Fleck, executive director of the Center for Food Integrity, said the study's approach is consistent with the balance sought by his organization of science, ethics, and economics. He expects the center will help facilitate meetings, ensure consistent internal and external communication, provide feedback based on research into consumer attitudes and priorities, and possibly recruit additional partners.

The study will complement ongoing research sponsored by the American Egg Board during which scientists have been identifying researchable questions in sustainable egg production, Dr. Armstrong said.

Officials with McDonald's said in a statement that the study will help the company decide on "sustainable egg purchases."

"Globally, McDonald's supports cage and cage-free housing (systems) as long as they meet our animal welfare guiding principles," Bob Langert, McDonald's vice president for corporate social responsibility, said in the May 21 press release.

Mark Klein, spokesman for Cargill, said his company sees the need for science-based research that could lead to improvements in egg production and avoid negative, unintended consequences. He said he could not provide details on the company's financial commitment to the project.

The McDonald's announcement immediately drew a critical response from the Humane Society of the United States, which is accusing the fast-food company of using the study to delay changes in purchasing. The HSUS argues there already is an abundance of evidence that battery cage confinement is detrimental to animal welfare.

The Humane Society announced ahead of a McDonald's shareholder meeting May 27 that an HSUS representative would introduce a resolution to phase in use of eggs from cage-free hens at restaurants in the United States. The shareholders voted down the resolution.

Dr. Armstrong said there are advantages and disadvantages to housing systems with and without cages, and some of those are unclear to the public or are emotionally driven.

Dr. Armstrong takes issue both with producers who say their birds' productivity indicates good animal welfare practices, and with groups who pick out segments of scientific research and say the chickens' welfare needs are not being met. He did not, however, identify any specific individuals or groups that have expressed such opinions.

"You've got to look at the bigger picture on both ends of the perspective," Dr. Armstrong said. "A holistic approach that involves collaboration is better than one involving single-slice participants who don't want anything to change or who want changes that are simply driven by emotions.

"Either end of the extremes is not based on science and should be avoided."

A commentary written by a nine-member scientific advisory committee sponsored by but independent from the United Egg Producers has similarly advocated for development and adoption of science-based animal care guidelines and use of a holistic perspective in considering animal housing systems. The commentary by the committee, of which Drs. Armstrong and Golab are members, was published in an August 2008 edition of Feedstuffs.

"Furthermore, it is clear that additional research is necessary to evaluate the potential short- and long-term effects of different housing systems not only on hen health and welfare but on overall sustainability," the commentary states. "Food safety, security and quality, vulnerability to food bioterrorism, the impact on human health, sustainable environmental practices, supply chain dynamics, and the economic impact for consumers must all be considered."

The AVMA policy "AVMA Animal Welfare Principles" states that development and evaluation of animal welfare policies, resolutions, and actions requires a balance of "scientific knowledge and professional judgment with consideration of ethical and societal values." It also states that procedures related to animal housing, management, care, and use require continuous evaluation.

"The veterinary profession shall continually strive to improve animal health and welfare through scientific research, education, collaboration, advocacy, and the development of legislation and regulations," the policy states.