I have never witnessed a normal shed by one of my snakes, but I have had to help one or two of my snakes shed due to humidity issues (normally when they are in QT in tanks). Just recently I had to help my corn shed everything but his head (he'd gotten that part off). I love the technique I learned from one of Adam's videos. You put the snake in a tub with a little water and put the tub in the rack. Come back in about 30-60 min and help them get the shed off. It comes right off and is so easy.