If you still want to switch over to rats give him a little time and then try again. He may refuse the rats because of their smell since he had a tussle with one. Try and get a f/t or pre kill a rat his next feed and scent it with a mouse or mouse bedding. If he wont take it, it may be the size of it that's putting him off. Start with something more comparable to the size of a large mouse and see if they will take it then you can slowly work your way up in size. Def see if you can get him started on f/t tho since a small rat live is around 4 bucks compared to about 1.25 frozen.