I came across an interesting opinion from a US farrier recently, an opinion that differs fundamentally from most farriers' opinions I have read or heard in the UK, where most farriers freely admit hooves are healthier without shoes but that shoeing is a necessary evil.
The farrier in question was quoted as saying that "farriery isn't just nailing on shoes, its a healing art". Now, its easy to take a quote like this out of context (particularly if you don't know what the original context was!) but the quote did seem to be implying somehow that shoes "heal" horses.
I'll freely admit that putting a set of shoes on a horse can dramatically improve the performance which an unhealthy hoof is capable of - this effect is, presumably, why most UK horses are shod - but I don't think they can "heal" a hoof (in the literal sense of "restoring it to health").
Shoes definitely have their place, and Sarah and I talked in "Feet first" about the fact that shoes will be the most practical option for many owners, but, certainly in the UK, farriers are under no illusions about whether its healthier for a hoof to be shod or not. You might think this is just barefoot bias on my part ;-) but listen to these quotes, from Martin Deacon, and David Gill, two well-known British farriers:
"Shoeing alters the natural function of the hoof wall...Metal shoes decrease the hoof's natural shock absorption."
"It is the combined complexity of the hoof and the almost naive crudeness of driving nails into what is effectively a thick piece of skin, which means that the chances of something going wrong are ever present. "
To be fair, both these farriers go on to write in depth about the use of shoes to affect limb and foot balance, and its maybe these changes to foot placement and limb loading that the US farrier views as beneficial. I wonder if his horses agree with him?