More visual aids to check for your horse's natural collection via some work in the classical dressage community...
Ironically, hyperflexion or rollkur bring the topic up to bear with some really nice photography, but all things horse, especially hoof care and on-the-ground handling, also affect your horse's collection.
A somewhat easy way to identify a corrupted body form is by following the diagonals at the trot.
These following 2 images are from Palindrome's horseandhound post.......
Close angles of incidence, ie angles in motion at the trot between diaganols, means relative collection. Although hyperflexion destorys collection at every level, destruction of collection can also be driven by a myriad of other things, including common hoof care practices and on-the-ground handling practices, as well as excessive confinement and other species-inappropriate common care practices.
The following are two photos from my home page slider (the horse is at the walk and not the trot).
All gaits engage diagonal weight bearing, including the 4-beat walk. Here, we have profiled angles of incidence on same-side limbs at the walk. Can you see the difference in quality before and after the trim?
I can. And so can he.