I find it hard to believe he is 100% sound.
He looks so irritated about the whole thing.
But, you asked about the headset. By looking at his neck, one can see that he has had some time, years perhaps, where someone spent way too much time worried about where he was putting his head, and perhaps snapping the reins on him to get that headset, and so he has pulled his neck backwards.
What does that mean? It means he has pulled his head back, like a turtle pulls its head backward, causing the part of the neck behind the 3rd vertebrae of the neck to arch up, and the part of the neck closer to the withers to drop down. It's not a true U neck, because it isn't conformational, but rather a result of making the horse tuck it's head back, possibly behind the vertical, and not riding the horse from the back to the front, meaning pulling the horse back by its face, rather than riding it up so that it naturally drops to a vertical position.
Last edited by tinyliny; 04-22-2019 at 04:25 PM.