Pinto Bean
refried sans lard
The idea that even those ponies who are supposedly hated or feared are still made to be comfortable (sometimes lavishly so) while being imprisoned suggests that ponies have, in general, vastly different views on the concepts of punishment, incarceration and reintegration than we do in our world.
I don’t think it would be a stretch to imagine Sprout eventually finding a new occupation, just not one with any sort of authority.