Thank you, They are just pets.For livestock in general, manufactured feed is easiest since it makes sure all nutrition is covered.
Of course pigs are often given slops/leftovers as a large part of their diet... but nutrition still needs to be watched. However, if you know the pig will be butchered soon, nutrition isn't as critical as with breeding stock, or pets.
I am guessing since you are asking for a pot belly, that this is a pet?
In which case, pelleted food would probably be best.