PS: I would not worry about pin firing. It used to be all horses at the track came out pin fired. I foxhunted with a few of those and they were fine.. it is just something done to deal with bucked shins (and it has been discovered that almost every 2 year old in training will get bucked shins even if they show no soreness.. it is part of bone remodeling for the work they have them doing).
At one time almost all race horses were pin fired to try to prevent bucked shins. It doesn't seem to work.. but some still do it.