Ours are always rubbing their manes - either on their neck covers (we don't generally use them for this reason) or because they lean through their post and rail paddocks for "tastier" grass on the other side.
Don't think flys would be the cause of mane loss but you can always put either a fly rug (ours wear sweet itch outfits which do a fly job - even though for us it is to stop their coats bleaching) or you could put on long lasting fly repellent (if there is such a thing) when you check them. Flys are usually worst around sunrise/sunset and around trees or water if you've got any...
DD's new pony has rubbed a little patch off his mane (initially from the trailer before the tail guard arrived, one journey) but, last night, it looked a lot worse and I am wondering if he's scratching in the field.
When I go down, doesn't seem bothered by the flies at all, but it has been suggested it might be flies.
His old owners assure me that he doesn't suffer from sweet itch etc, they didn't use a fly rug as they found it rubbed even with protection but used Coopers every few days, they said the flies seemed to go nearer his belly if anywhere.
What do people generally do? Could it be anything else?
Have ordered both Coopers and a fly rug but will send the rug back if required, just it's a hot forecast at the weekend.