Something else to keep in mind, is that consistency goes a long way with ball pythons. If they've been eating strong for a while, its not unusual for them to take a break from time to time. Trying different things week after week can cause more harm than good and set your ball back farther than they would have chosen on their own, all other things being equal.

Its insanely frusterating for keepers, but you've just got to tell yourself they're just being a ball python and go with the flow.