However I've been reading and I see some people saying to not shoe your horse just cause your going to run the road or harder surfaces and kind of slowly introduce them to it and their hooves will harden and come use to it. If that is true or not, I'm not sure.
Good question! I believe it's important for owners to do their own research & analyse both sides of the argument in order to come to their own decisions. Hopefully the thread link in my signature will get you off to a good start. I don't think any one answer is right for every horse & situation. Eg. Yes, it is most definitely possible that your horses can perform all you want them to bare, but it depends on different factors as to whether they *will*.
focus on the flat shoes and take it as a pro-con as what will be good out of have them shod and what are negative effects of having them shod.
Great way of looking at it I reckon. There are some who deny any probs with shoes, but IMO just about everything under the sun comes with at least a few side effects, so best to be objective about them. Sounds like flat shoes are all your guys would likely need, from what you've told, or IMO a better option would be tips - a short 'shoe' that just covers the front 1/3 of the foot, to give some extra grip when pulling.
I think a major 'con' of conventional shoes is that the peripherally load the foot(force the entire load onto hoof walls) and don't support/protect the rest of the foot. This of course is not such an issue with horses only working on soft/yielding ground. I think the biggest 'con' of keeping horses bare is that due to their management(diet, lifestyle, environment), they're often not well enough conditioned to be pulled out of a cushy paddock & be able to perform on every surface we may want them to. Domestic horses need hoof protection in at least some situations most of the time. But don't rule out hoof boots as one very good option, which do protect & support the entire hoof without further loading walls.
I also know there are a lot of people that go on about how it hurts the horse in the long run from pulling nails to circulation to the hard shock to horse.
Yep, I think that's a big thing too. IMO well applied shoes on a healthy, mature hoof on yielding ground is not such an issue to me. It's when they're kept on the horse long term (eg. Many months without respite) that I think the major probs happen. Tho as you may gather above, I also think they can be problematic when applied to immature or unhealthy feet, or when they're used to work horses on hard flat surfaces & such. Don't see nails as a big issue, but changes to circulation & vibration shock are issues IMO.
If cracking was the only issue that they were shod do they make anything else other than a shoe he could wear? And not be drugged for it...
Hmm, about the drugging - perhaps he lacked training &/or had some bad experiences with his back feet, which led to them becoming neglected & cracked? I suggest finding yourself a good, considerate & patient trainer to help him overcome his fear & responses, along with finding a considerate & patient farrier(make sure to inform him/her of the situation before they arrive).
As for the cracking, you don't need shoes to treat that & I believe further peripheral loading is actually more unhelpful. There are a number of reasons that horse's hooves crack. He may have a diet/nutrition problem that has contributed to weakened walls & allowed stressed areas to crack. He may have been left without good/adequate hoof care, so the overlong sections broke away & leverage caused cracks. He may have had stone bruises/abscesses which caused 'blow outs' which became cracks, &/or some wall separation allowed bugs to get in & the infection which is eating away at the inner wall tissue is perpetuating/worsening the cracks.
Examining & if necessary correcting the diet & balancing nutrition is important, for general health & hoof health, regardless of cracks. Frequent good trimming, to *keep* the hooves in good shape & *prevent* them from becoming too long(as opposed to allowing them to overgrow before 'correcting' as many do) is vital. Cleaning out the crack & treating any infection is also very important. In ideal situations, with good diet & trimming, it's possible for seedy toe to go away without further measures, but usually it needs treatment & if you don't, it can continue to eat away at healthy tissue as quickly as the horse can grow it.