The problem is a lot of people don't like to lend out their animals or take unknown stock onto their premises, this is one of the reasons we bought our own GOS boar even though we only have two sows, i did lend him out and he came back with a broken leg and had to be PTS

so would probably think twice about lending again!
You may have to be prepared to put a bit of mileage in on this one or find somebody who will do sow B&B.
mandy