He probably is hungry, youre not feeding him enough. Hatchling ball pythons usually start out on hoppers or small adult mice, pinky mice are too small for them even when they are right out of the egg. Feeding him an small adult mouse once a week is a normal schedule, no where near powerfeeding.
On the other hand, powerfeeding would be closer to feeding an adult mouse every 3 days. Thats when you end up with a fat, possibly unhealthy animal.