....."7) did her December injury catch up t her as she has not been exercising as much or as hard as before the injury, ....."
So she's a hard worker thats had a significant decrease in her workload for several months. I apologize that i cannot open your CH (says im not allowed?) to see what or if she was needing to consume to maintain weight for the intense training & competing and if it was decreased when her work regimen lightened. I also cant access her age or prior bloodwork but may be well worth checking her insulin before (or at least with) all the extensive bloodwork you listed (Selenium, VitE, Etc).
I have a rescued Saddlebred (my vet swears he's a NSH bc of his Arab-y croup and head) that had old blood in the white line in every hoof at every trim. My farrier assured me it wasnt a big deal and that most horses have that. I wish I had known to worry a little more so i coulda saved years of chronic hoof pain for my gelding. Though occ we had a good ride, for the better part of four years he was unrideable to the point of being dangerous, all bc his feet hurt. Now on a drylot & appropriate diet, my guy is a completely new horse with a wonderful attitude & is growing out much healthier feet. I wish we had more ASBs & NSHs in my part of the country (Northeast)...and more endurance riding!
Good luck, and im sure others will chime in asap,
Kerry in NY
Pinky Sept 2014
Tofurky Nov 2014