It really doesn't matter the "size" of the dog as adult or puppy. If at 8 or even twelve weeks(or younger in some cases), just don't know what to do with it, and need some help learning that it's food, and that they are supposed to actually eat it. Not that they can or can't handle it. They all can once they get it, but some, (even the size of Dane puppies) need some help getting started on occasion. And there are others, like yours just take right to it. Raw fed from birth, and they probably get it much quicker in most cases which is probably the case with yours.
So I guess in short, is that it's not the size a dog will be when grown, it's about a puppy learning what to do with raw bones to begin with.