Should be no problem.
If the pig's barn area is too large, they will make a bed in a corner, and then when they wake leave their bed, and then pee and poo, still inside your building. If you make the pigs indoor area small, they will then just treat it as bed, and pee and poo outside where you won't have to clean up after them!
Pigs will eat a chicken if they get hold of it, but as chickens scatter and outmanourvre pigs, pigs don't chase them so this is only a problem for an ill chicken, or one that decides to sleep with the pigs!