The nation’s largest meat producer says it has terminated its contract with an Oklahoma farm after NBC News showed the company undercover video of workers on the farm kicking, hitting and throwing pigs and slamming piglets into the ground.

“We’re extremely disappointed by the mistreatment shown in the video and will not tolerate this kind of animal mishandling,” said Gary Mickelson, a spokesman for Tyson Foods. “We are immediately terminating our contract with this farmer and will take possession of the animals remaining on the farm.”

The owner of the farm said that the video showed "mistreatment" of animals and he had taken action of his own. “I was stunned that anyone could be that callous in their treatment of any animal," said Lonnie Herring. "After viewing the video, I immediately returned to my farm and terminated the employees seen in the video."

The video was shot by an activist from the animal rights group Mercy for Animals from mid-September to mid-October as he worked undercover as a farmhand at West Coast Farms, an Okfuskee County business that supplies pork products under contract to Tyson Foods. The advocacy group says the actions seen on video and witnessed by its investigator violate a state animal cruelty law, and are contrary to Tyson’s policies on the treatment of livestock.

“This factory farm is hell on Earth for pigs,” said Nathan Runkle, executive director of Mercy for Animals. “Tyson has allowed a culture of cruelty and neglect to fester at this factory farm facility. This is some of the most sadistic and malicious cruelty to animals I have ever witnessed.”

Watch the video on Mercy for Animals’ website. Warning: This video includes graphic and sometimes bloody scenes

The undercover worker who shot the video, “Pete,” told NBC News that abuse was “commonplace and constant” at West Coast Farms. He said that it included hitting, kicking, throwing, striking animals with the edges of wooden boards, sticking fingers in their eyes, and leaving piglets to die slowly after they were slammed into the ground “in failed euthanasia attempts.” According to Pete, some of the piglets were alive 30 minutes after being slammed into the ground.

“On three separate occasions, I reported abuse to the owner,” said Pete. “After each report, the abuse continued by workers, and all of the workers I questioned told me that that owner had not spoken to them recently about animal handling.”

Pete said the workers told him they had heard about animal handling standards when they were hired -- when they signed forms from Tyson stating that they would not abuse animals -- but not since. Pete also signed the documents, and said that owner Herring “indicated he did not follow the Tyson animal handling forms he had me sign.”

Tyson Foods owns the sows and boars on the farm, while Herring owns the farm itself and provides meat to Tyson under contract.

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Said Mickelson, the Tyson Foods spokesman, “We’re serious about proper animal handling and expect the farmers who supply us to treat animals with care and to be trained and certified in responsible animal care practices. It’s consistent with our core values to ‘serve as stewards of the animals…entrusted to us.’”

Herring, meanwhile, denied that Pete had reported alleged abuse to him, and said his workers are trained in proper animal care and know abuse is not tolerated. He said that his farm uses approved methods of euthanasia on animals, and that the animals are euthanized in a humane fashion. He also said his workers are “trained and instructed” that they must verify an animal is dead “before [they] leave that animal.”

“It is a part of the business and there are prescribed methods of euthanasia and I follow those to a T,” said Herring.

After reviewing the Mercy for Animals video, he said he had "a renewed commitment to animal care" and planned to pay more attention to activity on the farm. "I can do better than this video shows and will do better in the future," said Herring.

Paul Sundberg, vice president for science and technology at the National Pork Board, a marketing group overseen by the federal Agriculture Department, explained that blunt force euthanasia is “common industry practice,” and that euthanasia was sometimes necessary because of ill health.

"During pork production,” said Sundberg, “there are times when animals become disadvantaged, meaning sick or injured, where the humane thing to do is euthanize them. I am a veterinarian -- I was in practice for nine years -- and in my experience there are things we can't treat."

Said Sundberg, “It is a judgment call. It's not unusual where any animal is ill or injured and can't be treated. It is better for the pig to euthanize them than have them suffer.”

According to the Oklahoma Pork Council, there are no specific state laws pertaining to the treatment of animals on hog farms. Farmers must adhere to "industry standards" set by the American Veterinary Medical Association.

On its website, the AVMA says that “despite its appearance,” blunt force trauma “can be an effective way to euthanize nursing piglets.”

“The fact is,” says the 2012 post, “that manually applied blunt force trauma to the head, either with an implement or by striking the head against a surface, has been shown to cause immediate unconsciousness and rapid death when performed correctly on young piglets. It must be performed correctly so that it does cause immediate unconsciousness and rapid death.”

According to the AVMA, blunt force trauma is effective because the frontal bones of the piglets’ skulls are not fully developed and they can be killed with a single sharp blow to the head.

Runkle countered that “slamming baby piglets into the ground can cause prolonged pain,” and that some animals survive for hours.

Renowned livestock expert Temple Grandin, an associate professor of livestock behavior at Colorado State University and an animal welfare adviser to the U.S. Department of Agriculture and the meat industry, reviewed the undercover video and said it was evidence that the farm’s employees were “poorly trained.”

“The behavior of the employees was abusive to animals," Grandin said. "Kicking and beating animals is never acceptable.”

Maxey Reilly, assistant district attorney for Okfuskee County, said she had seen information provided by Mercy for Animals, and that a legal representative for the group had asked her about filing animal cruelty charges, but that she wanted to learn more about industry standards.

“Until I’ve reviewed everything and done some independent research, I’m not ready to make a decision,” said Reilly. “If I do decide this warrants more action, I will still mount an independent investigation. I don’t want to be pressured into doing something that’s not right."

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