There's no need to switch to rats if you can obtain mice easily in your area and your snake will eat them. All of mine(about 37?) eat live adult mice with the occasional f/t weaned rat(I had leftovers from a black blood I sent off) for the big girls. Small babies get 1 adult mouse a week, juvies get 1-2 adult mice a week, subadults get 2-3 depending on the size of the mice and if the snake in question is male or female, adult males get 2-3 adult mice every 7-10 days, and adult females get 3-4 adult mice every 7-14 days, plus the occasional f/t weaned rat if they want it(garbage disposals).

They do perfectly fine on either and will grow at their predetermined rate regardless of what prey type you feed.