Hey There. I saw this on the online newsletter and thought I might be able to help pertaining to the crack.
Cracks will never grow out. They are usually caused by a underlying fungal infection in the hoof. They are not usually painful, but left untreated, lead to other problems.
Here is a really good video. I can say that her method works VERY well. I used it on my horse and it worked wonders.
Hope this video helps.