A lot of times, people who are overly reliant on supplements have holes in the horse care they are providing.
You identified one yourself-- poor quality hay.
All of the problems you are experiencing can be tied back to management issues. For example, ulcers and anxiety go hand in hand. Many horses who are overly spooky and anxious calm down when their ulcers are treated.
Ulcers can be caused by lots of things, but one of the most common culprits in boarding situations is not enough forage. If the barn was already feeding poor quality hay, there’s a good chance they might also be stingy with hay. Horses shouldn’t be going for any extended period of time without access to forage. It doesn’t necessarily need to be free choice 24/7, but they need to have enough forage provided so that they aren’t running out hours before the next feeding. No supplement or pharmaceutical treatment is going to help in the long-term if they horse’s ulcers are being caused by his management.
Forage problems also greatly increase the likelihood of colic.
Contrary to popular belief, OTTBs don’t have to have bad feet. It’s not something they are all genetically predisposed to. Most of the time it’s secondary to management, lifestyle, and nutrition. They don’t always get the best farrier work at the track and the minimal turnout exacerbates those issues… then we bring them home and their nutrition changes drastically, often creating gaping deficiencies in amino acids and trace minerals. Hoof supplements don’t fix these problems; many times they don’t even make a dent in them. Good farrier work, good nutrition, and a healthy lifestyle fix these problems.
Sorry for the proselytizing tone. I feel for you because you are likely being put in a compromising position by people providing subpar care. They aren’t providing your horse with a healthy lifestyle, then they try to “pass the buck” and make it your problem, suggesting supplements to fix their shortcomings. Horses are expensive enough without owners being guilted into buying supplements to fix the problems a barn created.