Not trying to put you off but have you thought what you are going to do with all that meat? How many freezers do you have? Pork wont last that long even in a freezer, I think 3 or 6 months max. The costs of abattoir, butcher and feeding to killing out weight. The pig poo the noise especially come feeding time. 10 or more is going to be quite hard to deal with, especially as they get bigger, how will you cope if 2 or 3 set about the smallest one? Not sure how big 130 metres is, but with 10-16 piglets going on pigs its not going to last long. As they grow you would need 4 or more large arcs. Then if you are keeping them all in the same run how are you going to separate for the final journey?
Seriously suggest just have 2, neutered males, you will get attached, until you taste your first home cured bacon, real sausage or incredibly tasty pork chop.
Good luck. HM