The Humane Society of the United States is almost single-handedly changing the way farmers feed America’s appetite for bacon, ribs, holiday hams and other pork products.

Under pressure from the animal-welfare group, food industry giants such as ConAgra, Kroger, Safeway, Compass Group, Costco, McDonald’s, Burger King and Wendy’s have agreed in recent months to require their pork suppliers to phase out the use of gestation stalls for sows. The move will require producers to keep sows in pens, rather than crates, which means redesigning bars and training workers. The industry has long argued that the stalls are needed to protect sows from hurting each other, and there are concerns that the added cost ending their use will make it even harder for independent farmers to compete with corporate operations.

Gestation stalls, like conventional cages for hens, “have been scientifically researched. They have been found to provide benefits to both the animal, as well as to the farmworkers who are responsible for the care of the animals,” said Kay Johnson Smith, president and CEO of the Animal Agriculture Alliance.

But Temple Grandin, a renowned expert on animal welfare respected both by industry and activists, says the way sows and hens are housed is by far the two biggest issues and that change is inevitable in both. Another issue, docking the tails of dairy cattle, is being eliminated, she says.

“The public is just not going to accept sow stalls,” says Grandin, who has advised a variety of companies, including McDonald’s.

To force changes in the pork industry, the Humane Society has released undercover videos taken inside various sow operations, including two this year near Goodwell, Okla., in the district of the House Agriculture Committee’s chairman, Republican Frank D. Lucas.

Restaurant and supermarket chains have given various goals for the phase-out, but Wayne Pacelle, president and chief operating officer of the Humane Society of the United States, said he expects the transition to be complete by 2022, the deadline set by McDonald’s.

In another attack on the pork industry, the Humane Society filed suit against the U.S. Agriculture Department to cut off a major source of funding for the National Pork Producers Council, the industry’s lobbying arm. The lawsuit claims the National Pork Board’s $60 million purchase of the “Other White Meat” slogan from the pork council was illegal because the board, a promotion and research group, is funded through a USDA-collected fee known as a “checkoff,” which cannot be used for lobbying. The Humane Society wants to stop any additional $3 million annual payments to the pork council under the contract. The council called the lawsuit “another desperate attempt by the radical activist group to severely curtail animal agriculture and take away consumer food choices.”

The Humane Society last month asked the USDA inspector general to investigate the use of checkoff dollars by the two groups.