How are you preparing your f/t rodents? A couple of my BPs are picky and won't eat if they don't think it's warm enough. I can't give you any advice on switching from mice to rats, because all of mine switched no problem, but the advice Kymberli gave you sounds pretty solid. The zombie dance works really well for me, but you sometimes have to be willing to wait them out. I've wiggled a rat for what felt like over 5-10 minutes once before she would take it. Also how often are you offering food? It took me 3 weeks to get one of my BPs to eat, she was very stressed from being shipped, but I only offered food every 6 days. Offering food too often will just stress them more.