Help, ball python trying to escape

[Bogertophis]

Snakes grow at different rates (depending on temps & available food & genetics, etc) so age doesn't say much.

I suspect he should be eating adult mice, not hoppers att, btw. And sources don't go by the same exact description (or body wts) when describing a size, so it's possible your hoppers are on the small side, & 2 really isn't enough. Some snakes will accept multiple rodents at one meal, others won't; apparently yours doesn't mind, but before you "stuff him to excess", you should WEIGH BOTH your snake AND the prey you're feeding him. We all have better things to do than to keep guessing. And kindly look at the posted chart, please.

FYI- about switching to rats- rats & mice smell and taste differently- some snakes love both, some are picky & don't wish to switch without a battle, so I wouldn't use up all your mice when you try a rat for the first time, until you get his opinion on it.

Without seeing your snake, AND without knowing his weight, it's impossible for us to know IF your snake is underweight or over, etc.

Has he ever been fed live prey? IF so you might want to have a vet check his stool for parasites*, just in case that's what's bothering him. (*They are transmitted via live prey, not frozen-thawed.)

Frankly I haven't the foggiest notion what you meant by "sausage" or "salami"? But maybe this will help you: