It must be a bully thing. Einstein drags his front feet too. He does it so bad that one day while we were out for our walk his one nail started bleeding because it wore down that far! I asked the vet what to do and he said either stop walking him on the cement or get him some shoes. Since I know Einstein would never let me put shoes on him, we now alternate our walking location to the field behind our house and the sidewalk in our housing addition.