Also is it both or just one nostril that is bleeding. If it's both then normally that means the blood is coming from the lungs, which is life threatening.
If it's just one normally it is ok he may just bleed but I would DEFINITELY get the vet out to check it. If it's the work he's doing, then you can try to adapt and fix it, if it's his food then you can change it, and if it's something else then your vet will give you the best options
Get him scoped. It could be a very serious condition. If it happens at rest, it could actually be life threatening. If it happens after work, he is a bleeder, and there are supplements for that. Either way, have a vet check him.
Well if it's caused by inflammation from food allergy to hay types then PLEASE do me a favor and get him checked out immediately.
It's not all the time. We think it's from his hay.
Check it out. Can be serious or not too serious. When does his nose bleed. Before or after you work him? Eating time? Is there a pattern?
You should get a vet to check him out
It could be lots of things. Either they are adapting to new weather, allergies, or a more serious health problem that should be looked at.