My boar experience is limited, although I have recently got a young neutered boar so I know exactly what stink you mean.
How old are your boys? I assume they are both fairly young. To me it sounds like the change in environment has made them need to reassert their dominance so this is what you are seeing, essentially it is a brand new territory for them.
I wouldn't have thought it would last a long, long time and once they have settled down then I would think the scenting would calm down a bit but I am no expert. As for whether it would happen every time you change- I honestly wouldn't know, I would have thought that once they are used to the fleece they would scent quite so much but I again can't be sure. Hopefully someone else will be along soon.