NEW YORK (CNN/Money) - An animal rights group released a videotape Tuesday showing slaughterhouse workers with a KFC Corp. supplier jumping on live chickens and slamming them into walls, apparently for fun.

The image above shows a Pilgrim's Pride worker holding a live chicken by the neck and is about to slam it into a concrete wall.

The footage was secretly taken by a People for Ethical Treatment of Animals (PETA) investigator who worked at the Pilgrim's Pride plant in Moorefield, W.Va. from October to May.

In the video, titled "KFC's House of Horror," employees at the plant were seen stepping on the birds, kicking them and slamming them against walls and floors.

"We are appalled at the treatment of the animals shown in the video," said a Pilgrim's Pride spokesman, responding to the video. "These actions are completely contrary to all of our company's practices and policies regarding the humane treatment of poultry."

The spokesman added that after an investigation, any employee found violating the company's policies on animal welfare would be fired.

In a written statement, KFC said it found the actions "appalling" and has placed an animal welfare expert at the facility "to monitor activity and ensure absolutely no animal abuse."

"We do not tolerate animal abuse by any of our suppliers, under any circumstance," the statement said, adding that the company told Pilgrim's Pride that, "unless they can definitively assure us there are absolutely no abuses taking place, we will not purchase from this Moorefield, West Virginia, facility."

The statement said that the facility sells to other fast-food outlets and is one of many from which KFC buys.

But PETA spokesman Dan Shannon said more action is needed.

"What will prevent animals from being tortured is audits of slaughterhouses, having experts go and visit these farms, visit these suppliers on an unannounced basis so workers know that they're being monitored and workers know if they abuse an animal they're going to pay the price for it," Shannon told CNN.

Pilgrim's Pride, the second-largest poultry producer behind Tyson Foods, won KFC's "Supplier of the Year" award in 1997, the New York Times reported.

Shares of Pilgrim's Pride (PPC: down $0.91 to $29.85, Research, Estimates) fell nearly 4 percent on Tuesday after the video was posted. KFC is a subsidiary of Louisville, Ky.-based Yum Brands Inc. (YUM: up $0.16 to $39.25, Research, Estimates).