Join Date: Sep 2009
Location: Tampa Bay area, FL
Oh my goodness. Is it really that bad to have reached the coronet band? Has your horse seen a farrier recently? I know its common practice to 'notch' a vertical crack to keep it from growing, but what you're describing sort of sounds like only the hoof wall is cracked, since normally vertical cracks like the one you posted stay vertical.
It can take up to two months for hoof supplements to start taking effect, but you may not see the effects in the actual hoof for up to 6 months. My suggestion would be to start applying a hoof conditioner to both your horses feet, it can't hurt :/