At 170° the chicken is never sitting in the "Danger Zone". It's within hot-smoke temperatures, so it is being cooked while being smoked and provided it gets up to an I.T. above 132° within four hours, it should be perfectly safe from a safety standpoint. If a turkey can withstand those temps from a safety standpoint then a chicken, which would come up to temp quicker, certainly can.
I have a friend who does a turkey every year at hot-smoke temps and I have to say it turns out pretty dang good (the skin is a bit leathery but the meat is succulent).
I usually spatchcock and go hot & fast, but whole chickens are cheap. I wouldn't be afraid to try one.