I have the opposite problem, since I prefer feeding mice (for a variety of reasons) - and I have ONE stubborn gal who only likes rats. Sometimes if I pre-scent the mouse with rat bedding, she'll totally go for it... other times she turns up her nose. Might be worth a shot, though! Some snakes also don't care, so they'll take whatever you offer. Either way, you probably should start with live rats first. Since they've only had live thus far, it might be too much to pull a "double-switch" (rats & f/t) at once.