Posse member Bryan Gooding preps whole chickens for competition at the first Blues, Bandits & BBQ cookoff in Oak Cliff. (Photo ©Chris Wilkins/Texas BBQ Posse) In barbecue and grilling, properly cooking chicken is a tough challenge. Much of the chicken served by backyard grillers and smokers, as well as barbecue joints, is overcooked. Probably because no one wants to undercook. Posse co-founder Chris Wilkins and I had undercooked chicken at two consecutive stops on a recent tour of Austin-area places. It’s jarring to bite into a piece of chicken and see small red splotches — blood — deep in the…