CHICAGO — McDonald’s and supplier Tyson Foods have made moves to sever ties with a Tennessee chicken farm after the restaurant chain found itself in the crosshairs of an animal rights group — one that uses hidden cameras to document abusive practices in the farmed animal industry — for sourcing poultry from the farm the group says mistreats chickens.

A Mercy for Animals undercover “investigator” worked at the T&S Farm in Dukedom, Tennessee, for about four weeks in July and August, the group said, capturing video with a small camera. T&S Farm raises chickens for the Tyson Foods slaughterhouse plant in Union City, Tennessee, which in turn supplies meat for McNuggets, according to the group.

In images released Thursday, chickens at the farm are seen being beaten and stabbed with a pole with a spike on it. The video also shows what appear to be sick and deformed chickens among those held in a vast and crowded holding area.

“These are not new issues. They’ve been on McDonald’s radar,” said Nick Cooney, the organization’s director of education. “We’re hoping this investigation will help them commit to phasing these practices out.”

Cooney said Mercy for Animals had contacted McDonald’s about its investigation but the burger giant had made no commitment to changing practices.

But on Thursday, McDonald’s released a statement regarding its expectation for suppliers, saying Tyson had cut ties with the farm.

“We believe treating animals with care and respect is an integral part of a responsible supply chain and find the behavior depicted in this video to be completely unacceptable. We support Tyson Foods’ decision to terminate their contract with this farmer,” McDonald’s statement read. “We’re working with Tyson Foods to further investigate this situation and reinforce our expectations around animal health and welfare at the farm level.

“We’re committed to working with animal welfare and industry experts to inform our policies that promote better management, strong employee education and verification of practices.”

Tyson followed with a statement from spokesman Gary Mickelson, confirming the move to sever its relationship with the farm.

“Based on what we currently know, we are terminating the farmer’s contract to grow chickens for us. There are currently no chickens on the farm,” Mickelson wrote.

Tyson’s alleged practices have been the subject of protests in other cities this summer.

McDonald’s, based in suburban Chicago, is the latest of several high-profile companies that Los Angeles-based Mercy for Animals has targeted to reform their practices by releasing video footage captured by undercover operatives.

Mercy for Animals has done more than 40 similar investigations, Cooney said. The practices captured on video at the T&S Farm are not unusual, according to Cooney, and an industry leader like McDonald’s should help change that, he added.

McDonald’s has made some changes in response to past animal cruelty reports, like vowing to phase out farms that use gestation crates for pregnant sows by 2022. It also cut ties with a major egg producer in 2011 after a Mercy video captured cruelty to hens and chicks.

After each investigation, Mercy for Animals doesn’t wait long before going to the press with its videos, Cooney said. “By and large, we want the public to know as soon as possible,” he said.