Can snakes just change their preference on frozen vs live rats over night?

I have a ball python and he has always eaten frozen rats. I thaw them under hot water and make sure they are a good temp. Well, the past four weeks it's been a struggle to get him to actually eat. He has been almost refusing to eat the rat. After about 30-45 minutes he'll lay on it and toy with it then finally eat it, almost like he's bored with it. So, a couple days ago my husband decided to try a live rat. The snake pounced on it so fast and ate it up no problem. Can snakes change their preferences like that and is it okay to just continue to feed him live rats for now on even though all he's eaten his whole life is frozen?