I don’t use guineadad specifically but I do use fleece bedding in my piggy shed but only during the summer months
You can only really use fleece outside during summer provided it isn’t a wet summer. Any moisture in the air will be absorbed by the fleece so piggies will always have wet bedding.
I think guineadads have to be handwashed otherwise they can shrink. I’m not entirely certain on that though.
I use the washer for mine. You could probably handwash them if you wanted to, but it would be quite difficult as they are a bit bulky. Also keep in mind that if you try to handwash them, any stains that your piggies make will probably not come out very well.
I hope that this helps!
They do shrink a bit in the drier, you just have to stretch them out on each side (and hold) for ten seconds.