There are no need for puppy mills,millions of dogs and puppies in shelters are euthanized because there are not enough with homes.
There may be exceptions but it seems puppies from puppy mills are not healthy
"When breeders are no longer able to care for their animals, the problem lands squarely on the shoulders of local shelters," said Half-way Home's Latisha Duffy, who works closely with breeders in Missouri to find homes for retired breeding dogs. "
First the breeders earn as much money they can on the dogs and when the dogs are exhausted and unhealthy it´s time for local shelters to step in and save them.
I believe it´s tax dollars which pays at least a part of it.