Puppy mills are places where purebred or "designer" dogs are bred solely for the money they can bring in, with no regard for the dogs' welfare.  The puppies are housed in overcrowded, unsanitary cages. Puppies are taken away from their mothers too early and are not socialized with either dogs or humans.  They receive minimal, if any, veterinary care, and inbreeding is common. Disease, genetic disorders, and heartworm are the norm. The breeding females produce one litter after another in cramped cages with no concern for their health. 

Puppy mill dogs are sold to pet stores and advertised on the internet and in newspapers. If you are told that a breeding facility is "USDA-licensed" or "USDA-inspected", that only means that minimal standards of food, water, and shelter have been met. It says nothing about meeting the needs or securing the welfare of the breeder's dogs. AKC registration papers also tell you nothing about the condition of the dog or how it was raised.

Reputable breeders want you to visit their facility. They ask a lot of questions in order to assess whether or not you will be a suitable and responsible parent for their puppies.  Responsible breeders also don't churn out puppies as if from a factory.  They generally have a waiting list because they have a limited number of litters born each year.

Those of you who have rescued puppy mill dogs know the difficulties these dogs can face. In addition to health issues, most have never been housetrained; have never walked on a solid surface or with a leash; have never lived in a home with vacuum cleaners, blenders and other appliances; have never climbed stairs; have never interacted normally with other dogs or people.

Here are two easy-to-read books that may help you make your puppy mill dog's life more comfortable:

The Cautious Canine - How to Help Dogs Conquer Their Fears by Patricia McConnell lays out a step-by-step plan for treating your dog's fears. 

May I Pet Your Dog?: The How-to Guide for Kids Meeting Dogs (and dogs meeting kids) by Stephanie Calmenson will help you protect your dog from unwanted advances by children (and adults).  This book is written for children from a dog's point of view; so, if you have children of your own, it's a gem.

Please use the links on the left under "puppy mill dogs" to find advice on rehabilitating puppy mill dogs and to join the fight to shut down puppy mills.