My farrier winced in sympathetic pain when he watched me lead Fritz from his stall. Every symptom I reeled off and every observation he made led to one conclusion - a deep abscess caused by a stone bruise, probably under the coffin bone, and working its way upward to the coronary band. As if to confirm it, today the hoof was warm in that area from the infection.
He trimmed the affected hoof to help put more weight on the back, to ease Fritz's pain a little. He also trimmed the back feet, but couldn't do the other front hoof because Fritz could not bear to put that much weight on his sore left foot in order to pick up the right one. But he moves a little better tonight.
My job is to watch for a bulge along the coronary band where the infection will try to find an exit, and pop it. It'll probably save him a day of pain before it breaks through on its own. It can't be worse than the abscesses I've drained in cats. Those things can be nasty.