Like the others have said there is so much variable in how big/small you ball is. Also a factor is how big the egg was, how much yoke the egg had, how soon it started eating, how big it was when it hatched. If your ball looks like a triangle (if cut in half) then he/she is thin. If she is nicely rounded she is fine. If she is little then feed her little things (ie hopper mice) if she is bigger you can feed her rat pups (or fuzzys). Good luck and give us photos!!! We love photos