Bracken is now known to be carcinogenic so I don't think I'd be in a rush to use it for bedding. Do some googling (and report back what you find out, please!
) because my recollection is that there's one time of year when it's at its most dangerous, which I
think is when it is carrying spores. Whether it is less or even not carcinogenic after it's died back naturally I am not sure.
Yes sheep graze in amongst bracken in many places - because they have no choice! Bracken harbours ticks, so if you have sheep in contact with bracken, you need to be de-ticking your sheep.
If the bracken that you have is removable then personally I would try to get it removed now, because if you leave it, it will just become more and more established and harder and harder to remove.
Again, do some googling (and report back please
), but I'm pretty sure it's one of those plants that needs to be damaged in order to die; just cutting it won't kill it off as it is so very deep-rooted. So bracken-mashing devices don't break the stems completely, just ravage them. It'll take several / many seasons to get it killed off. I think I read that there's a poison that'll do for it (but I think takes several applications.) Whether the take-up of the poison would be best after mashing and/or at some particular stage of growth I can't recall.
Sorry this is mostly hearsay / recollected readings so don't take any of it as fact! (Except the bits about ticks and about it becoming more established if not dealt with; those are from personal experience.)
Oh, and the other approach to bracken control is to reintroduce dinosaurs, I think?