When I tried switching over to rats...most of my snakes were OK with it. They even seems to be more agressive feeders! I had a milk snake that would only eat mouse fuzzies even though she was around 3 feet long. I tried rat pinks because they are about the sime size as the mouse fuzzies. Well, my milk snake LOVED them. Over the course of a couple of months, I have managed to move this snake up to weanling rats. She would NEVER touch an adult mouse, though!
I had some snakes, however, that refuse the rats. Unfortunately this makes it where I still have to buy mice, too. I was hoping to switch everyone over!
I have had the same thing happen with the color of the mice/rats as well. I have some snakes that will only take white food items...I've not figured that one out!