Not an easy business to get into, as most meat buyers are after a bargain or two.... so unless you have a regular buyer who pays promptly, quite risky. Careful planning needed IMO.
Most people do it using lamlac for a few weeks, but making it up thinner for goats than for sheep and I wouldn't wean them quite as early as lambs. Then feeding on cattle rations - look into feeding guidelines for Boer goats, should get some info on there... goat kids mainly kept inside - so problems are cocci and other "indoor" issues.
We rear out boys for our own consumption only, as I would not be able to make money on them, but the meat is out of this world.