The Rock County Sheriff's Office is investigating a Christensen Farms hog breeding operation featured on a grisly video from an animal rights group that appears to show workers abusing and neglecting sick sows and piglets.

Rock County Sheriff Sheriff Evan Verbrugge said investigators will visit the Luverne facility "hopefully in the next week," with an independent veterinarian. A graphic video, released Tuesday by the Los Angeles-based watchdog group Last Chance for Animals featured footage of emaciated, sick and injured pigs; farm workers hitting downed pigs, stabbing them with pens to make them walk, and dragging animals by the ears and snouts; and squealing piglets being euthanized in small containers pumped full of carbon dioxide.

Christensen Farms & Feedlots Inc. responded Friday by suspending seven employees and launching an internal investigation into conditions at the facility. The company, which is based in Sleepy Eye, Minn., is the nation’s fourth-largest pork producer, supplying large national chains like Wal-Mart.

Verbrugge said the publicity surrounding the video release will make the county's investigation more difficult.

"I'm guessing that when we get there with the veterinarian, it's going to be clean and there's going to be no issues," he said.

Last Chance for Animals counters that it released the video only after someone outside their group tipped off Christensen Farms. Adam Wilson, director of investigations for Last Chance for Animals, pointed out Christensen put out a press release on Friday -- four days before the group released its video.

Verbrugge said it would be up to the county attorney's office to determine whether the hidden camera footage alone would be grounds for possible charges. Animal abuse and neglect is a misdemeanor crime in Minnesota and no commercial farming operation has ever been charged under state statute.

Christensen Farms released a second statement Tuesday, pledging zero-tolerance of animal mistreatment.

“There is absolutely no place at Christensen Farms or in this industry for violations of animal welfare,” company CEO Glenn Stolt said in the statement. "The portions of the video we have seen are both disturbing and will be part of our ongoing internal investigation.”