I've started noticing that my horse has started to hit his heels / pasterns ( you hear a loud clicking/clapping-like noise) when he moves, mostly during transitions or at the trot.Thanks!
Trimming may be the issue, fronts left w/ too much heel (often done to try to correct) can be a problem. This will speed breakover but also shorten the stride length. Long toes front and hind can also be a problem.
If it's due to conformation then bell/over reach boots are in order.
If only noticed (or simply worse) under saddle, try picking his head up and working him into the bit. Will free up the shoulders and help the front get out of the way of the hinds.