cat cage
A picture taken on August 21, 2018 shows a cat looking out of a cage as it receives treatment before being offered for adoption at the SPA animal shelter (SPA - Societe Protectrice des Animaux - Animal Protection Society) in Gennevilliers, northwest of Paris. Joel Saget/AFP/Getty Images

Prospective pet owners in the state of California might not know it, but a new law going into place on Tuesday could make it easier to ensure pets did not come from breeding mills. Assembly Bill 485 goes into effect to start the new year, prohibiting pet stores from selling animals that came from the controversial breeding centers.

The bill, signed into law by governor Jerry Brown in 2017, blocks retail stores from selling cats, dogs or rabbits that came from breeding mills. Those animals will need to come from a “public animal control agency or shelter, society for the prevention of cruelty to animals shelter, humane society shelter, or rescue group,” according to the law.

It is the first such statewide law in the United States. It also requires pet stores to document exactly where the animals came from and make that information clearly visible on their cages.

The idea is to cut off the supply of pets from breeding centers that reportedly hold the animals in dismal conditions and instead support rescue organizations. The Humane Society of the United States estimated that there were 10,000 puppy mills in the U.S. as of 2016.

A fact sheet accompanying AB485 accused puppy mills of raising animals “without adequate food, water, socialization or veterinary care.” As a result, animals that come from those places can suffer from health problems and behavioral issues, according to the fact sheet.