I've always removed them, but more because that's what most buyers expect. However, the last litter I had two of the buyers specifically wanted them left on. Both stated they hunted on ice and in waterlogged areas and thought the dogs used their dew claws to get a better grip climbing over slick logs and ice. As that litter was small, I left all their dew claws on because at 3 days I had no idea which pup would go to those that wanted them left on (and the other buyers didn't care). Of my 6 dogs, I have one with her dew claws and while she's injured a nail on one, she's accident prone and has injured other toenails often and more seriously. Her one minor nail injury on a dew claw was just in keeping with the way she bangs herself up in general.