If you're going to breed her then I wouldn't switch. try and find a local mouse breeder and feed her larger mice. once you get her to breeding size and she has a clutch of eggs. wash her and her tub real good. wait a few days and then try the switch. some will eat what ever once their follicles start to grow. my females that are on soft furs will usually switch after having a clutch. If she likes mice and you try to switch her. it might take forever getting to breeding size. if you're thinking about breeding her. if not, wait her out, when she gets hungry enough she should change but like I said it could put her back in time for breeding.
to clear this up a little after I read it. some will eat before they have a clutch. when placing a male in with her and when her follicles starts to grow. some females will slam rodents and with some females, it doesn't matter which rodents they are.