In this picture you can see part of the "damage" It's right by his withers...it's sticking up straight...that was taken on Sunday...but on Tuesday he got more off (below it...not on that one spot).
I walked the fence and though I saw a few hairs...it was mainly hair from underneath his head when he stuck his head over the fence to say hi (or, heaven forbid, weave)...and a few pieces of what looked like his tail, but I can't be 100% positive if it was his tail or mane.
I was thinking maybe another horse was eating his mane, but he's turned out seperately and though the horses have access to the pasture right by him, they usually don't use it, and if they do they are eating the grass.
Again I'll get better pictures, but that will have to do till Thursday.
Do you think it looks like biting more than rubbing?
I don't think anyone cut his mane, I know the BO wouldn't...and I doubt the other girls would...
Note: if it's really hard to see in that picture I can put up a larger image of that picture