Horses that have foundered, have laminitis or are labelled "navicular" have a very good chance of returning to soundness. To do so requires a dedicated owner willing to make changes to their horse's diet, lifestyle and hoof care regimen. Through correct natural trimming, appropriate diet and movement, the horse can recover and return to soundness in nearly all cases. The exceptions are horses that have internal hoof structure damage, but even they can have an improved level of soundness with natural horse care.
In the photos above, the foundered hooves on the left are shown on the right after I trimmed the horse at proper intervals for several months. (The hooves do not appear that similar, but I assure you they are on the same pony.) This pony's condition was primarily due to a chronic metabolic problem, aggravated by pasture grazing and inappropriate diet, as well as infrequent trimming. The owners fully cooperated and as a result, their pony was able to recover from his uncomfortable, foundered condition. I have seen many seemingly hopeless situations turn out well after working with the owners.
In most rehabilitation situations, booting is necessary to assist the horse in recovery. Boots will help reduce the pain a horse is experiencing, so he or she will move around the turnout area. This movement increases the circulation in the feet and facilitates healing and new hoof growth. Not only does the circulation help recovery, but the pressure on the sole and frog is also critical to the development of adequate sole thickness and frog health.
Many horses are euthanized unnecessarily when foundered. I have trimmed a number of horses that the owners were going to have put down per vet or farrier recommendations. These horses recovered and are doing just fine thanks to improved natural horse care supported by their owners.