Correct sentence:
The kiang's hooves look like a horse's, but they are wider. They help the kiang not slip on rocks.
Why this is correct (simple steps):
- We use "kiang's" and "horse's" to show the hooves belong to them.
- Put a comma before "but" because it joins two short ideas.
- We use "they" to talk about the hooves in the next sentence so it sounds nicer.