We (Deeside, Scotland) have just agreed a winter grazing licence on well grassed but rough upland fields, with them having to bring their own fencing, they offered 35p per head per week which I was very happy with given the fencing aspect. we normally use these fields for hay so it will benefit that having the old grass eaten off and the ground fertilised. This year the baler broke so most is a mix of unmown standing grass, topped fields and some that we did manage to bale hay before balergeddon. So quite a bit to eat for them.
They will deal with escapees/casualties and any supplementary forage/feed, but they know I will keep an eye on them so they know of any problems, and also we will provide water. They will be off by end of Feb but I will probably do the licence agreement until mid or end of March as it might still be snowed in by end Feb.
I should add I know this farmer as he's nearby (which also makes it good for him as so convenient) and I am happy with his stock and his management of them, I would probably not have bothered to do it if I didnt have any knowledge of the person coming on.
Hope this is useful!