My guess is that he just needs a while longer to acclimate. Also, Bo Peep and Sir Not will not eat anything that moves and are very shy, so you might try doing what I've done that works with them: put in a dead mouse like you did with the rat and make sure the enclosure is good and dark (lights out, towel over the top, snake and prey in paper bag, whichever). But I'd give it at least a week, preferably two, before trying again.