Todd Marotz oversees thousands of pigs at several farms in south-central Minnesota, but he guesses only 20% of those barns are compliant to send hogs to California.

A new Golden State law took effect Jan. 1 that requires that any pork sold there must come from operations that offer livestock more space than in past practice.

As the most populous state in America, California holds some sway over U.S. hog farmers, consuming about 14% of the nation's pork supply. Many of the nation's hogs come from the Midwest, including Minnesota, which ranks second behind Iowa in number of pigs raised.

Other states may follow. In 2016, Massachusetts voters approved a measure banning the sale of pork products from sows raised in pens. A similar bill has been introduced in New York, rankling farmers in the Midwest.

"It's California kind of dictating to Minnesota producers how to raise pigs," said Marotz, who is head of production for Gaylord's Wakefield Pork, which raises some 50,000 hogs across the region. "We were hoping the Supreme Court would resolve this, but they failed to do that."

Pork producer associations fought the law, arguing it amounted to one state telling farmers in other states how to raise their pigs. But the law received the U.S. high court's blessing last spring.

Animal welfare groups say the law was necessary to change factory farming, which often includes close confinement for livestock, including sows — female, birthing pigs — contained for long durations in gestation crates.

The industry argued such crates prevent the sows from harming each other or workers. Now, many farmers and processors are resigned to accepting the rules.

Even before the Supreme Court's decision, Marotz was already getting his barns ready.

"This [law] has nothing to do with [animal] welfare," he said. "But the law is the law."

Marotz — like many pig farmers — believes environmental and animal welfare advocates are adding more red tape for his industry.

"We're all for a free market," he said, "But [Prop 12 was introduced by] animal rights extremists with a vegan agenda. That's really who wanted to eliminate livestock producers."

Marotz listed what he said would be the unintended consequences of the California law, including the high costs to remodel facilities and expanding the carbon footprints of producers who use more fuel to heat bigger barns.

The law took effect in July. But pork raised under the old rules, and still in the supply chain, could be sold until Jan. 1.

Pork producers say the new regulatory environment — driven by voters in California in 2018 when they approved ballot measure Proposition 12 — will drive up the cost of pork for consumers from San Diego to San Jose.

Jim Snee, CEO of Hormel Foods, the Austin, Minn.-based maker of bacon, Spam and chili, said last June that the company would "begin recovering costs from these investments." In other words, it would increase prices to offset the cost of compliance.

The pork industry says the new rules may put workers who handle the pigs in harm's way. Michael Formica, chief legal strategist for the National Pork Producers Council, in Washington, D.C., decried these efforts, which are largely led in states without hog farmers.

"There are worker safety implications," Formica said. "Sows are big animals."

There are concerns Prop 12 could even lead to increased clashes between hogs. Marotz said his barns have already seen a 5% increase in mortality for sows.

Nevertheless, supporters of the ballot measure won over public support, with 63% of California voters approving the measure that requires 24-square-feet for each sow.

So far, producers have lined up to send pork to California. More than 1,250 livestock producers and distributors were in compliance for Prop 12, which promises "cage-free eggs" and "crate-free pork," by the beginning of the month, according to the state's agriculture department.

Proponents say the law will also attract pork producers that prioritize raising hogs outdoors or in other less confined ways. That's welcome news to some pork farmers in Minnesota.

Josh VanDerPol runs Clara City-based Pastures a Plenty, a natural hog farm raising pork directly marketed to many co-ops in the Twin Cities. Since 1999, his family has raised hogs outdoors with natural bedding, first as part of the Niman Ranch brand and then independently.

"I think we come at this issue with a different perspective," VanDerPol said. "We have very different humane standards [than conventional hog farmers]."

VanDerPol's hogs, unlike confined animals, also have the freedom to go outside, soaking up "nice weather," he said.

"A day like today?" VanDerPol said on Monday as snow fell over the region. "They're going to come back inside as much as they can and hunker down until it blows over."

In a statement, Wayne Pacelle, president of Animal Wellness Action and the Center for a Humane Economy, said, "Final implementation of Prop 12 in the new year not only provides the prospect of dramatically better living conditions in American agriculture, but it provides a critical market for thousands of pig farmers who don't rely on immobilizing crates as a routine animal-housing practice."

Still, the industry is watching closely any hog welfare legislation or ballot measures across the country. Formica, the pork council's legal strategist, warned that the various laws could be "moving the goalposts," creating 50 separate pork markets. He noted, for example, that ground sausage is exempt from regulations in California, but not in Massachusetts.

Like farmers seeking to chase consumers, on the processing side, Minnesota-based Hormel says it has been in compliance with Proposition 12 for two years.

"Hormel Foods has produced Prop 12 compliant products since January 2022 and the company and its Applegate brand have had Prop 12 compliant products available in the state since that time," the company said in May.

Hormel is also studying "the use and prevalence of group sow housing throughout our supply chain" and plans to release its findings later this year.

For Minnesota's 3,000 pig farmers, who sold over 15 million hogs last year, those seeking to be Prop 12 compliant have hired auditors to prove to California their pork is raised under the new rules.

VanDerPol believes the new mandate might signal a potential sea-change in U.S. animal agriculture.

Sweden and the U.K. banned gestational crates decades ago, he said, and other European countries have banned concrete, slatted flooring for hogs.

"It's nice to see people appreciate some of the things we're willing to do," VanDerPol said. "Whether it's the customer who comes in the store to shop for a product or someone across the country."