Usually if they strike and constrict they will eat it. Are you feeding in a different tub, or moving the tub once it strikes? I have one that if I bother it at all, it will uncoil and it takes forever for the snake to start eating the rat again. I would feed the snake in the tub, close it, make sure you hear the strike and coil, then leave the snake alone completely for an hour or so. It should eat the rodent if it coiled.