I got to watch my brother-in-law Mike trim a horse's hooves. It was very interesting.
The hooves were ragged and split.
First, he cleaned the dirt out from inside the hoof with a special knife.
Then, he clipped off extra hoof with a pair of nippers. This does not hurt the horse at all. It's just like when you trim your nails.
Next, he used a rasp to file and shape the hoof.
Here is the finished hoof. Doesn't it look much better?!