Forty-eight yellow labradors have been placed into care and a 68-year-old man arrested in western Wisconsin for mistreatment.
According to the Pierce County Sheriff's Office, the dogs were found at an unlicensed breeding facility in Elmwood after a warrant was executed on Friday, with 35 dogs and 13 puppies transferred to a shelter in Golden Valley, Minnesota.
The labs at the suspected puppy-mill were found living in "small, filthy travel crates" with no access to food or water. Numerous dead animals were also found at the facility.
"What we saw here was no way for a dog to live," said Kathryn Destreza, of the American Society for the Prevention of Cruelty to Animals (ASPCA) in a press release.
"The puppies at breeding facilities are often sold for profit," she added, "but many people don't realize their parents are often kept there for years, subjected to incessant breeding and usually lacking basic care and socialization, resulting in a very poor quality of life."
Police were alerted to the facility after a tip from a "concerned citizen" who was "appalled" by the conditions they witnessed.
The dogs will be kept at the shelter in Golden Valley until their custody can be determined by a court.
The owner of the facility has been booked into the Pierce County jail on suspicion of having an improper animal shelter, not providing food to confined animals and animal mistreatment.