A dozen Chicago-area pet stores—including Alsip Home and Nursery in Frankfort —have been listed in a puppy mill investigation conducted by the Humane Society of the United States.

The Humane Society said Tuesday that undercover investigators visited 12 stores over a three-day period in October, and found many are linked to inhumane commercial breeders known as puppy mills. During the visits, employees at the stores denied selling animals from puppy mills, but documents showed otherwise, according to the Humane Society. Investigators also discovered that eight of the 12 stores were in violation of Illinois' pet shop disclosure law, which requires stores to post visible information about the animals and their breeders, the Humane Society said. The other four stores had information in binders that were not posted "in a conspicuous place on or near the cage of any dog or cat available for sale," according to the report.

The Humane Society also reviewed hundreds of Certificates of Veterinary Inspection documents, which show the origin of puppies shipped to Chicago-area pet stores. United States Department of Agriculture inspection reports for the puppy breeders were then examined for violations of the federal Animal Welfare Act, along with Illinois Department of Agriculture files on the pet stores themselves, which include public complaints and inspection reports. Investigators who visited Alsip found that the store did not conspicuously post breeder information, the report states. Instead, the information was available in a binder near the puppy play area, which the State inspector felt was "acceptable to satisfy disclosure requirements," according to the report.

The Humane Society also said that two dogs at Alsip were being treated for upper respiratory infections at the time of the inspection, and that state inspection reports reveal that the store received a complaint in 2011 about a puppy that was purchased and then found to be infected with giardia. The report says that many dogs in the store were bought from Heritage Puppies, a huge puppy breeder-broker in Iowa. According to the Humane Society, staff told the investigator that the store only buys puppies from breeders with small numbers of dogs.

However, "on a recent USDA inspection report for Heritage Puppies, the federal inspector noted 458 adult breeding dogs and 220 puppies on the property," the report says.

Alsip President Kris Shepard told Patch that the store takes every possible precaution to ensure that it does not buy from puppy mills. Shepard said Alsip purchases from Heritage Puppies only when Heritage is serving as the broker. Puppy brokers assist breeders in marketing their animals.