Alternatively, you could do the chicken and ribs at the same temp, the sacrifice being virtually no chance at crispy chicken skin-- if that's what floats your boat. I don't find it that big a problem personally because I don't eat the skin-- it's where a lot of fat resides.
My last chicken came out great and was prepared this way: I slipped my fingers up under the breast skin on either side, and then held the bird neck side down and sprinkled some McCormick's Montreal Chicken Seasoning in the pockets created. Then I rubbed the rest of the outside of the bird with it as well. The chicken went on the bottom rack, next to the chuck roast, and under the ribs on the top rack. I cooked at 240*, measured at the top grate. At about 3.5 hours, I checked the temp in the breast with my digital (semi)instant read thermometer-- 165*-- done. I wrapped the bird in heavy foil and rested it in a dry ice chest-- breast side down-- for about 1.5 hours until dinner time. It was great then, and also when reheated a few days later.
Now, if you ask me about a turkey, I'd tell you brined, definitely 325-350*, dry water pan. I can wait 4 hours for a chicken, but not the time it would take to do a much larger turkey at the lower temp range.
