Make two piles of coals
on opposite sides of grill and light. Add hickory chips to hot coals, if desired.
Combine salt, pepper, brown sugar, garlic powder and onion. Sprinkle over chicken
and rub into skin and cavities. Set chickens on the grill toward the middle, away
from direct heat. Cover and grill 1 to 1 1/2 hours until golden.
While chicken is grilling, combine barbecue ingredients and leave sitting out
at room temperature. During last 15 minutes of grilling, brush sauce over chicken.