From a collaboration of my trainer, vet and new farrier I came to the conclusion that shoes would be the best option right now.
And I absolutely, positively would not want or expect you to take my word for it blindly. You have to do your own homework and make the most informed decisions you can... and stay open minded. But that also means not taking your vet's & farrier's word blindly either.
Unfortunately, there are many, many farriers out there that don't have a good understanding of hoof balance & function, and vets, understandably, as they have to learn SO much about so much, unless specialised in hoofcare, often know less than farriers about those specifics. There is a LOT of pretty recent research that has been done that has radically changed the understanding about hoof function, so even formally educated professionals may not be up to date. So not at all judging them on it, but just do your own homework... On that note, the forum link in my signature is one good place to start.
I will speak to the farrier about what you have said to see if there is a reasoning to the way he did the set.
I imagine it is because he believes hooves should be peripherally loaded, that he doesn't understand the disconnection that he's seeing, or what he can do about it &/or that to fix a conventional rim on hooves, you need some hoof wall to nail to, so it must be a compromise with feet like that even with the best knowledge.
He is worked on sand/clay and we have an arena with fleet footing. When he was barefoot the only trouble I had was out on the trails, he would be very tender in the rocky areas.
Oh, it sounded like it was a general prob, that he was tender in the pasture & needed shoes for his arena work. Yes, as with people who never go barefoot on rough surfaces, gravel can be hard on bare feet if they're not 'well calloused'. In addition, at 4yo, he will only be beginning to develop(assuming environment/management allows it at all) the caudal foot strength he needs to have strong, sound feet.
If he only needs protection out on the trail, then there's no worry about showing, as you can just leave him barefoot the rest of the time when you're not on gravel. But another (far better, for function/health) option that is definitely allowed in showing is Easyshoes or Eponas or the likes.
Just curious, if you had a horse that lost a chunk of hoof like this one, what would you do? Before I had the farrier out I was thinking of doing a hoof boot while it healed,
The 'chunk' he lost is in the separated wall. It is a 'symptom' of the problem, not a problem of itself. I wouldn't worry about the chunk specifically - and it's not going to 'heal' any more than a broken fingernail will. I would have been concerned & working on improving his feet long before the chunk happened. I would be reassessing diet, nutrition(I'll look at earlier post on that, must have missed), and environment/management, and I'd be trimming him in such a way as to reduce the mechanical stress on his walls and facilitate them to start growing down well attached. And if there is any infection present in the white line(there very often is, but it can't be seen with shoes on), I'd be cutting it out if/as necessary and treating it topically. Especially if you're expecting wet weather, I wouldn't want anything fixed to the base of his feet & hindering treatment/drying out of infection. I'd also try to provide somewhere he can be at least part time, that is dry & allows his hooves to dry out.