HSUS explains that the reason why all pet stores are guilty of purchasing puppies from mills is because a responsible breeder won't sell puppies to a pet store. (thedodo.com)
[17] A high population of puppies from mills are inbred due to uncontrolled breeding. (en.wikipedia.org)
This pet shop chain obtains puppies from mills, including some with serious USDA violations. (caps-web.org)