NORFOLK, Va. — An animal rights group Thursday released an undercover video that shows Tyson Foods workers abusing and cruelly killing chickens at Virginia breeding facilities, prompting the company to fire 10 employees.

“We’re disgusted by a video showing improper treatment of birds,” the Arkansas company tweeted to its nearly 50,000 followers.

Christine Daugherty, a Tyson vice president, wrote in a statement that she was “outraged.” She said the workers “were all trained in proper animal handling, yet chose to ignore it.”

The company said it will “aggressively re-emphasize” its animal welfare policies to workers and end a practice known as “boning.” It involves inserting a piece of plastic in a male bird’s nostrils to stop it from accessing a female chicken’s feeder.

The film released by the Washington, D.C.-based group Compassion Over Killing is one of several taken in recent months at poultry facilities.

Animal rights groups contend the industry still treats animals inhumanely despite publicity over more compassionate practices, such as adding windows to poultry houses.

The three minutes of footage show workers smacking fluffy white chickens and swinging them by their legs and wings. One worker steps on a bird’s throat as it appears to suffocate. Chickens are crammed into cages. Some are crushed under vehicles.

“The best way we can protect chickens, and all animals, is simply to leave them off our plates,” the film’s narrator says.