Courtesy photo

A chicken at Soul Food Farm

When Jonathan Lewis was the owner of a fashion company, he suspected that the high-end zippers he imported were being surreptitiously replaced with lower-quality models.

Now Lewis runs a San Francisco meat-buying collective called Pastoral Plate, distributing humanely raised chickens from local farmers. He had hoped his days of distrust were over.

“I learned that whether you’re selling handbags or chickens,” he said, “it pays to be careful.”

Last year, Lewis believed that one of his farmers was getting birds from unknown sources and passing them off as her own. He also visited a ranch where, he said, cattle were supposed to get organic food but were instead receiving much less expensive conventional feed. Lewis declined to reveal the farms’ identities but took his business elsewhere.

Among a small group of aware consumers, concern about their meat’s origins is growing, according to Carolyn Dimitri, an associate professor of food studies at New York University. Though factory-farmed meat is still the big seller, some shoppers are willing to pay two or three times as much as supermarket prices to guarantee that the animals they eat were raised on organic or foraged food or both, had ample living space and sufficient time outdoors, and were not fed antibiotics or growth hormones.

Sam Mogannam, owner of the upscale Bi-Rite Market in San Francisco, said his customers were very savvy about where their meat came from.

“It’s pretty easy to display a heavily edited picture of a happy pig in a pasture,” he said. “You ultimately have no idea how their animals are treated.” So Mogannam encourages his head butcher, Chili Montes, to spend time developing close relationships with farmers. Montes visits most of the farms, traveling as far as Uruguay. He inspects the animals’ housing conditions and the types of feed they receive.

The Local Butcher Shop in Berkeley sells only meat that has been humanely raised locally. The animals must also live outdoors all the time. Monica Rocchino, the owner, said that she decided against one farm because chickens were kept in pens made of netting to protect them from predators.

Jonathan Lewis

Pasture-raised chickens at Amber and Son Farm

Alexis Koefed, owner of the small, family-run Soul Food Farm in Vacaville, said that the vast majority of farmers were straightforward about their animals’ living conditions and diets. “Even if we wanted to be dishonest, our customers demand transparency,” she said. "It’s very easy to just drive over and inspect our farm.”

When Lewis inspected the Amber and Son farm in Sebastopol last year, he recalled, Amber Faur, the owner, thrust a slaughtered chicken into his hands and told him it had been the leader of the flock — and a mean bird.

Though Lewis said he was initially caught off guard, he realized Faur had developed an intimacy with her chickens. It was because she “hated that hen that I realized how much she loves her animals,” Lewis said. “We’re buying all our chickens from her now.”

This article also appears in the Bay Area edition of The New York Times.