Im in the same boat. Got my ball 3-4 weeks ago. He was over 3 years old and weighed 390g. Not sure of his diet so i started with feeding a large mouse every 4-5 days, after 2 weeks of that i decided to go up to a small rat. He now weighs 470g. Either switch to smaller rats or start feeding multiple mice or a mouse multiple times a week. The snake will digest a small meal rather quickly. Mine would be hungry after a large mouse after 2-3 days. A rat holds him over for a week.