WEST MANSFIELD, Ohio – Concessions by farmers in this state to sharply restrict the close confinement of hens, hogs and veal calves are the latest sign that so-called factory farming – a staple of modern agriculture that is seen by critics as inhumane and a threat to the environment and health – is on the verge of significant change.

A recent agreement between farmers and animal rights activists here is a rare compromise in the bitter and growing debate over large-scale, intensive methods of producing eggs and meat, and may well push farmers in other states to give ground, experts say. The rising consumer preference for more natural and local products and concerns about pollution and antibiotic use in giant livestock operations are also driving change.

The surprise truce in Ohio follows stronger limits imposed by California voters in 2008; there, extreme caging methods will be banned altogether by 2015. In another sign of the growing clout of the animal welfare movement, a law passed in California this year will also ban imports from other states of eggs produced in crowded cages. Similar limits were approved last year in Michigan and less sweeping restrictions have been adopted in Florida, Arizona and other states.

Hoping to avoid a divisive November referendum that some farmers feared they would lose, Gov. Ted Strickland of Ohio urged farm leaders to negotiate with opponents, led by the Humane Society of the United States. After secret negotiations, the sides agreed to bar new construction of egg farms that pack birds in cages and to phase out the tight caging of pregnant sows within 15 years and of veal calves by 2017.

Farmers in Ohio have accepted the agreement with chagrin, saying they sense that they must bend with the political and cultural winds.

Tim Weaver, whose grandparents started selling eggs in the early 20th century, is proud of his state-of-the art facilities, where 4 million birds produce more than 3 million eggs a day. In just one typical barn here at his Heartland Quality Egg Farm, 268,000 small white hens live in cages about the size of an open newspaper, six or seven to a cage.

Weaver said that after his initial shock at the agreement, he has accepted it as necessary. He will not be immediately affected since it allows existing egg farms to continue but bars new ones with similar cages. He defends his methods, saying, "My own belief is that I’m doing the right thing."

Egg production is at the center of the debate because more than 90 percent of the country’s eggs are now produced in the stacked rows of cages that critics call inhumane.

Ohio is the country’s second-largest egg producer, after Iowa. In the modern version of an egg barn, hordes of hens live with computer-controlled air circulation, lighting and feeding, their droppings whisked away by conveyor belt for recycling as fertilizer. As the hens jostle one other, their eggs roll onto a belt to be washed, graded and packed without ever being touched by human hands.

Weaver insists that his chickens are content and less prone to disease than those in barnyard flocks, saying, "If our chickens aren’t healthy and happy, they won’t be as productive."

Keeping chickens in cages is cruel and unnecessary, counter advocates like Wayne Pacelle, chief executive of the Humane Society of the United States, which has played a central role in the state-by-state battles.

"Animals that are built to move should be allowed to move," he said in an interview, and for chickens that means space for dust-bathing, perching and nesting.

The assertion that animals must be happy to be productive is not accurate, Pacelle added, pointing to abnormal behaviors like head waving or bar-biting and to a loss of bone density in confined animals.

In the mid-20th century, developments in animal nutrition and farm technologies as well as economic competition spurred the emergence of large-scale farms, often driving out small farmers who could not afford the large capital investments or survive the lower prices.

Now, the United Egg Producers, a national trade group, says that egg prices would rise by 25 percent if all eggs were produced by uncaged hens, putting stress on consumers and school lunch programs. Animal proponents say that better noncage methods could be developed and that price is not the ultimate issue anyway.

The American Veal Association, under pressure from consumers, agreed in 2007 to phase out the close confinement of calves by 2017. The requirement in the California law and the Ohio agreement to phase out the use of "gestation crates" on hog farms will have much wider effects.

The family of Irv Bell, 64, has been growing hogs in Zanesville, Ohio, since the 19th century. Where males and females were once put into a pen to mate, sows are now inseminated artificially and most are kept through their pregnancy in a 2-by-7-foot crate, in which they can lie down but not turn.

"I work with the hogs every day, and I don’t think there is anything wrong with gestation crates," he said. "But I have to be aware of things on the horizon, the bigger things at work."

Formally, the new Ohio agreement only makes recommendations to a state livestock standards board, and getting opponents to recognize the authority of that board was an important achievement, said Keith Stimpert, a senior vice president of the Ohio Farm Bureau Federation.

"We all know change is coming," Stimpert said, adding that farmers would also respond to demands by consumers and restaurants for free-range products.

"But is this how we’re going to deal with these issues, on a state-by-state basis?" he asked.

That timetables and rules differ among states is going to cause economic harm, he said.

The Humane Society of the United States, for its part, is already picking new targets. The advocates have the most leverage, Pacelle said, in the states that permit referendums. He said that the issues were likely to be pressed in Washington and Oregon. Winning concessions may be harder, he acknowledged, in states without referendums, including Iowa and the South.

Meanwhile, a new dispute over chicken cages is already brewing in California. The breakthrough 2008 law said that animals could be confined only in ways that allowed them "to lie down, stand up, fully extend their limbs and turn around freely." Egg producers and even some animal advocates say this may permit housing hens in larger "enriched cages," with perches and nesting spots.

Pacelle asserts that no form of caging can meet a chicken’s needs for "running, flying and wing flapping," and that denying these impulses can cause a rise in stress hormones.

"There’s going to be a legal wrangle over this," Pacelle predicted.

© 2010 The New York Times Company