id also start to breed rats as i do because the rat gets to a good size quick for ball pythons from juvi to adult, youd end up wasteing alot of mice, IMO. for example i have a girl that is 2700g after dropping eggs and she is about 4500-5000g when shes ready to go again that would be 675g for 15% of her weight and a large adult mouse is about 45g....675g divided by 45g = 15 mice a week!!!!!!!

and on the light side for her at 2700g would be 15% at 405g which would be 9 45g mice a week...still alot

hope this helps