In 2015, a new anti-puppy mill law took effect in Chicago that changed the landscape for pet stores. The law prohibits pet retailers from sourcing animals from anywhere except government run animal shelters, or animal control, or non-profit pet rescues, or pet shelters. Basically, pet stores are no longer able to source animals from pet breeders.
The law was not passed to put the squeeze on pet stores, but rather to protect consumers and save tax payers money as the city spends $500,000 annually to euthanize animals (some of which are adoptable). As one might expect, pet stores and breeders banded together to file a lawsuit to stop this new law. After losing at the district court level, the pet stores and breeders suffered another loss in the Seventh Circuit Court of Appeals, after a rather long wait. The case was argued back in May 2016, but the decision just issued September 21, 2017.
Commerce Clause Challenge
The opponents of the puppy mill law argued that the dormant commerce clause applied. It was alleged that by passing the puppy mill law, the constraints on state and local governments read into the commerce clause were violated.
The appellate court went to great lengths to explain in detail why the commerce clause, even the dormant one, did not apply here. In short, the court said that if the commerce clause were to be applied here, it would likely have to be applied to every law, as almost anything can arguably have an impact on interstate commerce. Rather, the court explained that because the law was facially non-discriminatory against out of state puppy breeders (as compared to in state breeders), only a rational basis test was needed.
State Constitutional Challenge
A challenge was also brought under the Illinois Constitution. That challenge alleged that the law violated the state constitutional principal of home rule. Since Chicago falls under the state's grant of home rule power, and the state explicitly granted municipalities the power to regulate animal control and welfare, this challenge was rather simply overruled by the appellate court.