[Cazador]

Ditto Don's comments,
Snake poop has two parts: a dark part, which is the feces, and a white, powdery part, which is the uric acid (it's the reptillian equivalent of urine). You'll often see these two parts side-by-side in the same pile of excrement, or sometimes you see the white part alone. If you're brave enough, pick up some of the white part and see if it crumbles. You might be mistaking this part (the uric acid) for bones.

You see the snake's skin between the scales because the snake has expanded after a large meal. This is normal. It will stay expanded if you continue to feed it often, or it will resume its old shape if you don't feed it for 2-3 days. This is all completely normal.

Rick