Quote Originally Posted by Souva View Post
Should I do this gradually, like how I built up to feeding him rats on a weekly basis? Or should I immediately switch?
I would just switch him to an appropriately-sized feeder every two weeks for now. You don't want to push him to catch up to where he "should" be, given his age. He will get there in his own time, and it's safer and healthier if he's fed on a two to three week schedule.

Also you should read through the feeding info in this thread, it's very informative, especially if you're rehabilitating an underfed critter.
http://ball-pythons.net/forums/showt...python-feeding