An international animal welfare group claims that a supplier of pigs to Hormel Foods Corp. had treated the animals cruelly, and called on the Austin-based company to immediately require changes from its suppliers.

Hormel suspended its buying from the supplier, the Maschhoffs, until a “thorough investigation” is completed. The Maschhoffs also initiated its own investigation into the claims.

Mercy For Animals on Tuesday presented an undercover video that showed workers castrating piglets and slicing off their tails, which the group said was done without any pain relief and caused injuries and illnesses that were not treated.

The 3-minute video also showed mother pigs in gestation crates with little room to move and biting on the steel bars.

Cody Carlson, a spokesperson for the group, said the video was shot at a sow factory farm in Hinton, Okla., owned by the Maschhoffs, one of the largest U.S. pork producers and a Hormel supplier.

An investigator for the animal welfare group was hired as a farmworker and shot the video in November and December while wearing a hidden camera, he said.

The animal rights group released the footage the morning of Hormel’s annual shareholder meeting.

Hormel officials responded that the company has a strict code of conduct for its suppliers and policies related to animal care and welfare.

“We will not tolerate any violation of these policies,” the company said in a statement. “As such, we have issued a suspension of all The Maschhoffs LLC Oklahoma sow operations while a thorough investigation is completed.”

Hormel said it has also dispatched certified third-party auditors to the Oklahoma farms and to additional Maschhoffs sites “to verify our animal care requirements are being adhered to.”

The Maschhoffs responded by opening its own investigation Tuesday morning.

“We have launched a full-scale investigation in response to this video,” said President Bradley Wolter in a statement. “Any animal care deficiencies discovered will be addressed in the quickest manner possible.”

The company immediately issued warnings to its employees and farm managers that The Maschhoffs have a “zero tolerance animal care policy.” It also plans to retrain all of its Oklahoma employees on “proper production procedures” and make every farm manager watch the video.

Hormel has been the subject of undercover animal rights filming before. In 2015, Compassion Over Killing released undercover footage of hogs being beaten by workers at Quality Pork Processors plant in Austin, which only supplies Hormel.

Carlson said Mercy for Animals was calling on Hormel to prevent animal mistreatment and suffering throughout the company’s supply chain, including installing live-stream cameras to deter abuse.

“It’s not a matter of identifying rotten eggs or cracking down on a rogue worker,” he said. “This is a matter of changing standard industry practices that enable and allow blatant animal abuse.”

One of Mercy for Animals’ key complaints in the video about the Maschhoffs is its use of gestation and farrowing crates, which separate sows during and after birth.

Hormel is transitioning all of its hog farms to group sow housing, which allows for more mobility. Hormel-owned farms, located in Colorado, Arizona and Wyoming, will be 100 percent group housing by 2018. But about 94 percent of all Hormel pork is raised by suppliers, according to recent company securities filings.

Lee Johnston, an animal scientist at the University of Minnesota’s swine program, said gestation stalls are common in the industry, but group housing systems are becoming more common.

“Gestation stalls have the advantage of keeping the sow isolated from the others. Sows are terribly mean to each other. They will have a lot of aggressive habits,” Johnston said. “With the crates, we can control their health a little better. Obviously, she can’t turn around and that can be a challenge for some folks looking at that.”

The video also highlights sows biting at bars, which the activists say is a sign of distress. Johnston did not levy judgment. “You often don’t know all the context behind the video and how they were shot.” But from an industry standpoint, he said, “sows always bite the bars right before feeding. There’s a lot of livestock that get excited right before you feed them.”

Johnston did voice concern over the jammed alleyways for the little pigs.

“That’s not a proper pig handling,” he said. “In those weaned pigs, you would probably move 10 or 20 at a time. That way they won’t get [frightened] and they move much more freely.”

Temple Grandin, a Colorado State University animal scientist and one of the most respected voices on animal welfare, gave Mercy For Animals a similar response, which was published to the organization’s website.

“The handling of the weaned piglets was definitely not acceptable and was rough. Too many small piglets were placed in the alley at a time. Much smaller groups of piglets should be moved,” Grandin wrote. “The next segment showed castration, which is a normal industry practice.”

Grandin added that “the pork industry needs to develop methods to provide pain relief.”

Unfortunately, there are no FDA-approved analgesic, or painkillers, for use on animal livestock, Johnston said.

“There’s a lot of discussion in the industry around drug companies and they have to seek approvals from the FDA,” Johnston said. “Producers don’t have a product they can use that’s approved in this country.”

If the testicles are not removed, he said, the boar gives off “a very offensive odor” once it matures that is transferred to the meat.

“It would be an unacceptable consumer product,” Johnston said. “So boars have been castrated for generations to take care of that problem.”

The castration depicted in the video shows bloodied piglets following castration. Johnston said “there’s usually very little blood” and expects those workers to be retrained.