I would imagine that their hooves will grow in proportion to their body growth. They would have to in order to support themselves. In other words, the hooves of a 80 pound doe will not support a 300 lb buck. If that's true, two bucks, both 6 years old with one weighing 300 lbs, and the other weighing 200 lbs will have different sized hooves, specific to their own body growth.

I do know that once you put an arrow thru the lungs, they don't grow at all.