Depending upon the size of the snake, 1-2 mice per week is plenty of food for them.

A lot of keepers feed every 7 days, and if you feed multiple items, feed them back to back. For example, you feed one mouse, wait till they swallow it, give them a few minutes to settle, then repeat the process.

Some people argue that this is better because it gives their system time to wind down after they digest the meal, as opposed to constantly having new food in their stomach every 4-5 days. But honestly, when a ball is young and growing, their metabolism is very fast anyway, so, feeding young balls at that interval isn't a bad thing.