Not too many of the dogs I bred had them on the rear legs.Every dog I know right now has or had rear dew claws except my friends two Goldens who don’t have any dew claws at all cause they were likely removed.
Libby has her front ones but her rear ones were removed. I can tell she did have them because you can see where they were removed. Franklin has both front and rear and like I mentioned earlier, one double due to being part Pyrenees.
One of the dogs I watch has both front and rear.
Gator I think had both front and rear but I don’t remember.
So out of 6 dogs, 4 have rear dew claws. Which I guess is why I thought most dogs did. But maybe our dogs are weird.