His symptoms are stiff gait at the trot in the front right especially. Also, because I believe he is part spotted saddle pony, he resorts to a lateral pace gait in transitions down from the canter to trot whenever his back is sore and he feels unbalanced and is putting all his weight up front to take the pressure off his back end.
I purchased a Thin Line brand "ultra" contour pad last January and that helped immensely. Do you think saddle fit has anything to do with this problem?
I use a Prestige Eventer cross country saddle with foam panels, 17 seat and medium (33 cm) tree. He has bulked up some since I purchased the saddle for him 2 years ago when he was 6 years old. Thanks for any advice!