Snakes will sometimes eat their foood item backwards. Mine will sometimes do this when their food item is smaller than what they can eat. when they eat it head first, the legs of the mouse, rat folds at a position that makes swallowing their prey easier. most snakes will eat their food properly but it is not uncommon for a snake to eat one the wrong way. The poop will just come out backwards

And once you get your temps in your enclosure set properly. you don't raise it when they eat. Too low of temps, they don't digest their food correctly, and sometimes they don't digest it at all. and too high of temps the food gets metabolized too fast and they don't get as much out of it as they could of.