Other views/facts on puppy mills:
A puppy mill, sometimes known as a puppy farm, is a commercial dog breeding facility that is operated with an emphasis upon profits above animal welfare and is often in substandard conditions regarding the well-being of dogs in their care. Similar types of operations exist for other animals commonly kept as pets or used as feed for other animals. The term can be applied to operations involving other animals commercially bred for profit, e.g. "kitty mills." There are an estimated 4,000 puppy mills in the U.S. that produce more than half a million puppies a year. Commercial kennels may be licensed by the United States Department of Agriculture which may inspect the kennels routinely.
For-profit breeding on a smaller scale is sometimes referred to as backyard breeding.
http://en.wikipedia.org/wiki/Puppy_mill