My youngest is 10, and while I take him with me, he is not ready to be a shooter. I let him take his BB gun and practice safe gun handling. He sometimes finishes off my cripples with it. It make him feel like he is really involved. Not saying your son isn't ready, but mine is not. As a side note, I would personally NOT hunt with someone else's 10'yr old carrying a shotgun in the quail field. Deer stand or duck blind YES, but not walking around quail hunting. Too much room for error.
^^^^^^^^^ Agree with this. Not because of his age or maturity level necessarily....its just that shooting birds over dogs (and walking) is all very dynamic. Unless you also have a person to stand directly behind him to coach and intercept any errant swings with the shotgun...I would not consider it.
There is just too much that can go wrong in the excitement. Some type of stationary hunting where shots are strictly controlled would be a better way to introduce him to shooting 'game' which is quite different than shooting clay birds.
By 12 yrs. old...there will be a VAST difference in his maturity and thought processes. Sure, each child is different (and they ARE still children at that age) and no doubt someone is going to chime in how they started hunting age 7-8 or whatever, but generally speaking...12 yrs. old and up (after demonstrating safety and proficiency) is where I start considering letting them handle a firearm all on their own.
Too, the fact that you are soliciting opinions here...rather suggests you have concerns/reservations as well. Follow your intuition on this one.