Patience is key, And yes you can go back to mice, but if he's been consistent for a while on rats, dont break just yet till weight loss... You could also try live rat pups? as they wont harm your snake. As for aggravating to force to eat isnt always the best way, itll just make then punch it with there face! Aswell as stressing them out even more. But it wont make him any less/more docile, which most of them usually are =)