**WARNING: Viewers may find the video in the report above difficult to watch. It is graphic.
DENVER -- An animal rights group went into a northern Colorado business with a camera to shine the spotlight on what it says is cruelty to newborn calves.
It's a problem that has captured the attention of criminal investigators in Weld County.
Most of the calves are male. Dairy farms don't want them because they don't produce milk.
The video was shot at Quanah Cattle Co., a calf-raising facility owned by J.D. Heiskell & Co., a large commodity trading and livestock feed manufacturing company.
"Heartbreaking ... and illegal." That's how the advocacy group described the alleged treatment of newborn calves.
A member of the group Compassion Over Killing took the undercover video of calves at the Quanah Cattle Company in Weld County.
The Weld County Sheriff's Office confirms that investigators have seen the video and have launched an animal cruelty investigation.
Quanah workers pick up newborn calves from area dairy farms and then keep them in crates or pens for about a week before shipping them off to the slaughterhouse or calf-raising farm.
This type of facility is not regulated by the U.S. Department of Agriculture.
But Dr. Temple Grandin, an animal handling expert at Colorado State University says if it was it would be shut down.
The undercover video shows workers dragging the calves by the ears, legs and tails. The USDA prohibits that treatment.
Dr. Grandin points out some of the calves are so young you can see umbilical cords, and that's too young for them to have been removed from the dairy farm.
There are also pictures of dead calves.
Robert Hodgen, A Quanah manager, says he never saw that kind of treatment. But after seeing the undercover video he says he took immediate action.
"Absolutely I was unaware. That's not how we want to do business."
Hodgen says he has launched his own investigation and promises going forward that animals at the facility will be treated safely and humanely.
The manager says Quanah has just a handful of employees and he met with all of them Wednesday to make sure the treatment seen in the video is not occurring at the facility any more.
There are about 200 young calves in the buildings at Quanah's facility.