Well, I have a 7 year old who can legally hunt in NC with a muzzelloader, shotgun, or rifle. He can't pull back the required legal weight on his recurve yet but he has been shooting his pappa's crossbow and is hitting the boiler-room everytime at 20 and 30yds.
Why shouldn't he be able to hunt with a crossbow?
It would extend his season by over 2 months if he was able to use a crossbow during archery season.