I have a gelding with a crack in both of his front hooves. He's lame on gravel and perfect everywhere else. He's currently barefoot, and has been for a while.
The cracks starting appearing a month or two ago. They have been getting progressively worse instead of growing out. Does that mean I should shoe him?
They currently look like this:

He is on an all-around supplement, and is getting 2.5mg of biotin a day from that. Should I be giving him something else?
I haven't talked to my farrier about it yet, because they were barely noticeable when he was last out. He's coming again in a couple weeks, so I'm going to talk to him about it then. I'd just like to be somewhat informed before I talk to him, so I'm not just taking everything he says for granted.