Ball pythons should never really eat pinkies, they are too small. You should start them on hoppers or very small adult mice if you can't get baby mice or baby rats.
k when i bought him i got pinkies which are almost gone and some fuzzies im a rookie here i figured out real quick the pinkies were to small just tryin to use them up got three left fuzzies?and whats a hopper? and back to my original should i feed him more?
The link below will tell you what the sizes of mice and rats are. Depending on the largest girth of your snake and weight of the snake will determine what you can really feed him/her..
Most of my babies have been put on med mice right out of the egg. Pinkies are never an option for me unless I have a stubborn eater. I did have a friend who got twins in an egg and they were so so tiny that a rat pink made a full belly. But for normal hatchling full grown mice can be eaten. For anything older go with rat weanlings or mice. Prey has to be moved up according to size of the snake.