PETALUMA, Calif. (AP) -- In a stretch of Northern California known for scenic shorelines and celebrated vineyards, hundreds of brown-bodied hens waddle around a large barn at Weber Family Farms.

"You provide them a stress-free environment with water, with food, with fresh air at all times, make them free of illness -- and they're going to reward you whether they're going to give you milk, eggs or meat," owner Mike Weber said, proudly showing off his business that has hundreds of thousands of chickens.

But some animal rights advocates say such large farms like Weber's are a problem.

Kristina Garfinkel said she doesn't believe in confining tens of thousands of chickens in facilities that provide no access to the outdoors, and she argues that these massive operations are actually crowding out small egg and dairy farms and making it hard for them to stay in business.

Garfinkel, lead organizer of the Coalition to End Factory Farming, has been campaigning for a ballot measure aimed at putting an end to large-scale confined animal agriculture in Sonoma County. Proponents say the move is about the humane treatment of animals. But critics contend it is a misguided effort that could harm local egg farming and dairies.

Residents in Sonoma County, which is home to half a million people north of San Francisco, will vote this fall on the measure. The proposal would require the county to phase out what federal authorities call concentrated animal feeding operations, or farms where large numbers of animals are kept in a confined setting.

The measure is supported by animal rights activists. But it has also stoked a tremendous backlash, with residents posting massive numbers of signs along roadways, in front yards and on farmland opposing Measure J.

Weber said California already has strict rules about how animals must be treated, with farmers required to keep records, have annual inspections and provide space for livestock. He believes the measure would put his family's more than century-old farm -- one of a series of county farms that were walloped last year by avian influenza -- out of business. His commercial egg farm produces organic and conventional eggs as well as organic fertilizers.

"To come out with a blanket statement that all animal agriculture is bad, therefore it's our mission to get rid of it, is absolutely unreasonable, and it's not American at all," he said.

Garfinkel said 21 large-scale farms would be affected by the measure and would be given time to downsize their operations.

"It just impacts the largest, most destructive farms," she said of the measure.

In 2018, Californians overwhelmingly voted for a statewide ballot measure requiring that all eggs in the state come from cage-free hens. The nation's most populous state had already previously voted for another measure to enhance the standards for raising such animals.

Kathy Cullen, who runs a farm animal sanctuary, said she opposes confining animals for any reason. But Cullen said proponents aren't trying to shut down all farms, but rather asking them to change, and that the measure has helped create more awareness about farm animal welfare.

Farmers feel the measure has created awareness, too, about the challenges they face, said Dayna Ghirardelli, executive director of the Sonoma County Farm Bureau. Many local communities oppose the measure in a county that has a long agricultural history and had more than 3,000 farms in 2022, according to national agricultural statistics.

The county is especially known for wine-grape growing, but it also has dairies and poultry farms, as well as farms that grow vegetables and apples.

"If we can find a silver lining, to a certain degree, it's bringing the community together," Ghirardelli said.