To help ease your mind on the food, don't worry too much about the schedule. It's nice when it works, but real life often gets in the way. If he's not hungry, he's not going to eat, which is why it's almost impossible to "power feed" a ball the way some people do with boas. I'm happy he was willing to take a rat for you, some of them are very difficult if not impossible to switch once they've been on mice for extended time periods. To be honest with you, he probably is quite hungry. 2 or 3 mice (or one small rat) is a rather small meal for a 3 year old. How much does he weigh, and could you give us some details on his set up? What are the temperatures in his enclosure? If it's too cool, he may be having trouble digesting his food, which would of course make him rather uncomfortable.