For cracks you could try putting thrush treatment in them to kill any bacteria in the crack and that will help it grow out. If conditions outside are dry try using either hoof oil or coconut oil on their feet pit it on both the outer wall and on the sole/frog. For wet conditions if their feet are getting mussy try pure iodine to harden them and apple cider vinegar to keep them disinfected. When your farrier comes I wouldn't let them put shoes on. Hammering something onto already bad feet is never a good idea. If the area they are kept is really hard or rocky I would consider hoof boots to help protect the feet. We had a horse at our barn awhile back taht needed them.