Becky, what are the weights of your prey sizes? I have found that some people have rat weanlings who are about 50g *coughconniecough*

When I buy f/t rats, smalls are about 55g and mediums are about 80g. Could you post the weights you are talking about since maybe the OP is just getting very small sizes of what he's calling medium...

To the OP: Becky is insanely remarkably good regarding the care and husbandry and medications for ball pythons. She is a great resource as a member on this site. She singly helped me to save a little hypo female who was in the process of starving herself. Becky's advice is always geared to the health and welfare of the snake. I would take her advice without question!