Keep a very close eye on them, because they tend to kill one another. If you start seeing one get beat up separate them immediately, or you will have a dead bird. They are a very entertaining bird to watch. I know it is not good practice, but I keep my Chukar in as natural of a environment as possible. If you do the same they tend to dig, so bury your sides down a foot or so. build them a little rock mound for them to climb on this will help their toe nails (this is only if you have them on dirt). Although I myself don't do this you should elevate them off the ground.
Enjoy them they really are a fantastic bird to have, and watch I love mine.
Good Luck
Daren