First and only post is to defend CA. So your horse is doing better on Timothy and alfalfa than he was on high NSC safechoice and very little forage. Good. Glad to here you added some quality forage and decided to attribute his success to non organic oats. Your problem was you weren’t feeding him well to begin with.
My horses eat the most diverse organic diet of any I know, pulling it up from the ground with their teeth like nature intended. And it took me decades to develop pasture that would eliminate the need for any supplements. Please don’t ride in here condemning intelligent advice with an attitude that you are providing better quality anything by feeding non organic feed from a bag. Which Tim/Alf pellets are you feeding? And you do realize that you are only echoing what everyone said, the horse will need vitamin/mineral and other supplements to be healthy on this feed. So thank you for confirming what everyone here told the OP.