1st time BP owner looking for help

[satomi325]

Feeding
I agree that he should be fed rats at this point; they are more nutritious and will help him put on weight quicker. You should feed him a rat that is a little bit bigger than his girth once a week on a specific feeding day. If he is really underweight or scrawny, then you might even want to lower the time between feedings. Also, I recommend using frozen rats, if possible. A live animal could be additional stress on him.

Another thing that might help is some extra supplements (calcium and Vitamin powder) to help him heal.

I have to politely disagree here.
Rats are not any more nutritious than a mouse. If you look at the nutritional value of prey, the only difference is that rats have a slightly higher fat content, which is only just a percentage or two more.
Snakes will gain more weight on rats due to the sheer size of the rat vs the size of a mouse. It's just easier to feed an adult BP a single rat than multiple mice.

I agree with Heather. If the snake is feeding on live prey, he should stick to live prey for the time being until he is 100% settled. Balls are known picky eaters and often go off feed. Switching prey all the sudden may add to the stress. And some snakes may never take rats or even frozen due to their picky-ness. 80% of my snakes refuse frozen and will only take live.

Supplements (Calcium/vita powder) don't really do anything. For lizards, yes. Snakes, not so much. They get everything they need from their food.