While it took me a couple of years to admit that I couldn't get them to switch, I have 3 that are live mousers. Since I have started offering live mice to those snakes, they have put on weight so much faster than when I was attempting to get them to eat rats.
Yes, now I breed mice too, only because of them, but I have found that to be a very easy thing to do. I ended up with 3 colonies of 1.5 mice, in order to keep up with their appetites. At times I do have a few to many, my normal total count on mice is about 150 - 175, but it makes it real easy to start a new colony when one becomes in need of replacement.
Hope this helps,
John