What happens to animals in pet stores that don't get sold?

I would never buy a dog or cat from a pet store knowing that the puppies come from puppy mills. But I am just wondering, what happens to the ones that don't get adopted?

well some dont have a happy ending but lots get given to a place like dogs trust or a place like that

If a dog is in a pound for too long without getting sold it will eventually get put down.Edit: Why the 3 thumbs down? its the truth!

In the pet shop where I work, in the UK, where we don't have dogs/cats in pet shops, we just keep the pet until it's sold. If it gets too old, it goes in our Adoption Centre, or occasionally it will get sent to another store. They are never put to sleep or put in shelters.Adoption Centre information-http://www.petsathome.com/aboutpetsathome/pets-at-home-charitable-foundation/support-adoptionWe ONLY have small animals in the centre, not dogs/cats, but our funding- donations from the centre, from people buying the animals- goes to charities that house dogs and cats.

I used to work in a pet store when I was 16. My very first job. It saddened me... I went to work there because I love animals. When a dog doesn't sell, they keep reducing the price the older it gets, and if it still doesn't sell, it gets shipped back to the puppy mill where they will either return it to breeding stock, or put it to sleep. It's very sad, but it's the truth. One example was an Afghan hound we had. He was there for so long, he was getting so big that he couldn't fit in the cage anymore. His price went down to $349 (from $899) and finally when I came to work one day he was gone. I only hope that he got sold...

I think it really depends on the store.