It is okay to see a faint outline of ribs. It is not okay for a horse to lose unnecessary weight after a diet change.
Also, is he *really* ribby, or just appearing to be? He is sedated, all his muscles in his back and over his ribs will relax and "sink." My mare looks ridiculous when she's sedated, but that's not really what she looks like. The ribbiness you see here could be an illusion. Posted via Mobile Device