In the shorter term, the fast-food giant said that it would work with producers and suppliers to develop traceability systems to prove that the meat it buys are not from farms that use such structures.

The company also said that, by 2017, it would seek to source pork for its U.S. business from producers that are also working to phase out such gestation stalls.

McDonald's, the top U.S. hamburger chain by sales, vowed in February to work with its U.S. pork suppliers to phase out the use of gestation crates, which confine animals during the breeding and post-birth process. The policy shift will apply only to the company's U.S. business, company officials said. The 10-year plan comes amid an increasingly fierce battle over on-farm practices between farmers and agribusiness on one side and food safety groups and animal-rights organizations on the other.

The Humane Society of the United States, a leading critic of the use of gestation stalls, said that McDonald's announcement marked the latest victory for animal-rights groups.

"We wish the company planned to get rid of these crates tomorrow, but we understand the logistical challenges involved in making such significant improvements," said Paul Shapiro, vice president of farm animal protection for the Humane Society.

Everett Forkner, president of the National Pork Board, said the plan would place significant economic pressure on smaller hog operators who do not have access to capital, and may not be able to afford the cost of overhauling barns.

"The additional expenses on farmers forced to make this conversion could increase the risk of them having to leave the business," said Forkner, who also farms in Richards, Missouri.

Gestation crates are typically metal enclosures, about 7 feet long and 2 feet wide, in which a breeding sow is housed for much of her adult life.

Pork producers say these enclosures are necessary to protect young piglets from being crushed by larger animals, and to keep sows from fighting as they often will when housed together in larger pens.

"I know on my own farm I moved from open pens to stalls many years ago because too many sows were being injured or denied feed," Forkner said. "When sows are thrown together they can become very aggressive. Dominant sows physically attack the others, bite them and steal their food."

Animal rights groups say such stalls constitute inhumane treatment of the animals.

Other companies have either followed suit with their own plans or are vowing similar changes in regards to how they source their meats. Wendy's Co, the No. 2 hamburger chain in the U.S., made a similar announcement in March. And pork producers Smithfield Foods Inc and Hormel Foods Corp have said they, too, are phasing out the use of gestation crates in company-owned facilities.

McDonald's said it will take years to shift such production practices in the agricultural industry, in order to ensure that there is enough swine being raised in open-housing in order to meet the volume of pork products that it purchases.

"There are not enough sows housed in non-gestation crates right now. It's between 6% and 10%," said Bob Langert, vice president of sustainability for McDonald's. "It can't supply our needs."

 From the June 1, 2012, Prepared Foods’ Daily News