In an excerpt from The Essential Hoof Book, writers Susan Kauffmann and Christina Cline share information on the toe crack, one of the most common types of hoof crack.
. . . toe cracks are most often due to a combination of mechanical stresses in the toe region paired with compromised laminae that cause a lack of good connection between the wall and the coffin bone.”
Source: Horse Network, March 25, 2021. Link. Preventing cracks from happening in the first place is always better than trying to fix them after the fact. Make sure horses don’t suffer from “lack of farrier disease,” as overgrown neglected feet are highly vulnerable to cracks.