Confining a pregnant pig inside a narrow gestation crate where the sow is virtually immobilized, has been banned in nine U.S. states and the European Union, according to the Los Angeles-based nonprofit organization.
"Pork sold in Walmart stores comes from pigs who are abused, neglected, and sentenced to lives of extreme confinement and deprivation in crates," said Letten. "This is blatant animal abuse that no socially responsible corporation should be supporting."
Walmart spokeswoman Danit Marquardt said the Arkansas-based chain holds its suppliers to high standards and does not tolerate animal mistreatment.
"We think constructive dialogue and a collaborative approach is the right path to the right solution," Marquardt said. "We are currently engaged with pork suppliers, food safety experts and other organizations to work towards an industry-wide model that is not only respectful of farmers and animals, but also meets our customers' expectations for quality and animal safety."
The protests were sparked by hidden-camera footage secretly recorded in July at Minnesota-based Christensen Farms, a Walmart supplier, showing pregnant pigs confined in fly-infested crates barely larger than their bodies, pigs suffering from bloody open wounds and infections, and piglets being slammed into the ground and having their testicles ripped out and tails cut off without painkillers.
Recording similar secret footage in Utah could be problematic under state law. Last year, lawmakers prohibited anyone from photographing farm animals or animal operations under "false pretenses." Violators could face six months to a year in jail. Animal rights groups protested the bill.
Representatives for Christensen Farms have not returned requests for comment about the protest.
Protester Shay Baldwin of Salt Lake City said she could no longer support the world's largest retail chain because of its practices. She also said that she hoped others would be willing to pay more for food processed more humanly.
"Of course I would pay more," she added.
But Walmart shopper Paris Morgan, who was not part of the protest, said "it doesn't matter how you feel. When you don't have a lot of money and you need to buy groceries, you save whenever and wherever you can to get the food you need."
Protesters said the Salt Lake City demonstration was among more than 100 such events organized at Walmart stores nationwide.