If you are considering the ethics
of buying a breed dog, because of all of the abandoned animals out there, then good on 'ya.
However, I would strongly suggest that you stick with proven breeds for the game and terrain you want to hunt. I'd recommend finding some hunting partners with dogs for your first couple of seasons. Your local chapter of Quail. unlimited, Pheasants Forever, Ducks Unlimited, or whatever conservation organization exists for your target game would be an ideal place to start. You'll not only meet potential hunting partners, but the habitat work that these organizations do will get you out in the fields where the game is, and will therefore produce some good hunting spots as well.
Hunt with some old hands, and watch their dogs. Try hunting those same areas without a dog. After a couple of seasons, you'll know how YOU like to hunt, and will have seen some dog work. That will allow you to make an informed choice as to what kind of dog you want.
Then, if you're still committed to adopting, (and again, good on 'ya if you are,) contact the breed rescue organization for that breed and they'll match you up with a dog that will fit your needs.
Your odds of getting a good hunting dog at the local shelter aren't good, although you may very well get a great dog... that won't hunt worth a darn. Finding and retrieving game is work for a dog, and you need a dog designed for that work.
--Shannon