My neighbor has a darling little chestnut colt, whom has a mild case of something. His coat has 'clumped' up in a few places on his hindquarters (when you run your hand over them, they feel like bumps). The bumps resemble nasty stings, but are not. The clumps will pull off if you pick at them.
I once had a old gelding that had the same thing, but far worse. For the life of me I can't remember what it was called or how it was treated. Can anyone help? I want to get this guy some sort of treatment plan before this colts problem turns into a huge issue.