I know that trot poles and hill work are great for building topline, but I would assume those would be for horses that are at least slightly fit. I also know that tummy lifts help. I love scratching a horse's stomach (I love the face a lot of them make) so that's easy to do.
So where should I start with building a topline in a horse that has had minimal riding time in the last few months? I just got his horse and am switching his feed over to pellet/beet pulp mix and trying to keep as much hay in front of him as possible. Hopefully that will help fill it in. I also read that protein is good for filling in the back, should the amount of protein (14%) in the grain be sufficient? Is there such a thing as a protein supplement, and would that be something to look into?
I am an expert lunger, so any lunge exercises I can do?