I've never had a snake that didn't take rats a adults that started out as mousers. Never. And I've had quite a few. My founding females were raised on mice, because that was what was readily available. All of them converted to rats. A few were a little stubborn, but I was more stubborn. Once they switched, I never had a problem with them staying on rats. Nor have I had a problem switching a ball python started on ASF's or fed ASF's as their primary diet to rats.
If you research online, you won't find any studies on the nutritional requirements of ball pythons. It could very well be that mice are nutritionally sound for the needs of ball pythons, and the additional nutritional values in rats are just overkill, and waste. Just like too much of certain vitamins and minerals can be bad for you. No one can unequivically say that rats are "better" for ball pythons than mice, and no keeper should be made to feel that they are not caring for their animal properly if they feed mice rather than rats.
From a convenience point of view, rats would be more a more efficient way to feed for the keeper than mice (one prey item per feeding vs multiple prey items per feeding). But there's no scientific evidence that rats are "better" for your snake than mice, since no one has done a study on the nutritional requirements (amount of protein, etc) for a ball python (or any other snake that I'm aware of, for that matter).
I'm curious though - what supplements would anyone be giving their ball python, given that we don't know what needs to be supplemented? I certainly don't supplement.![]()