A few months ago we had a big family celebration and I cooked up a feast of BBQ food including pulled pork, sauces, salads and these BBQ smoked chickens.
The birds were rubbed with a little olive oil and BBQ rub (equal parts of smoked paprika, garlic salt, white pepper and granulated sugar) then left to stand for an hour while the smoker came up to temperature.
I own a Pro-Q Frontier Bullet smoker that has a coal pan at the bottom, with a water pan sitting above it as a heat-stabiliser and 2 grill racks (see picture below to see how it fits together)
To get the smoker going I lit a load of charcoal in the coal pan (I prefer coconut charcoal briquettes if I can find them). Once the charcoal is lit I inserted the water tray and stackers, placing 2 chickens on each shelf.
Then I scattered some smoking chips onto the hot coals, closed the access doors, but left the vent at the top open, and waited. When the temperature dial on the top of the smoker climbed to 200F I knew it would cook fine. All you really need to do is open the bottom access hatch and scatter more wood chips from time to time to ensure a good smoked flavour.
After about 3 hours I checked the internal temperature of the chickens using a meat thermometer and they were cooked.
I pulled them from the smoker and placed them in an oven dish and placed them in my gas barbecue where they were cooked for another 20 minutes on full heat with the lid closed, to crisp up the skin.
The chickens were then removed from the heat, covered in foil to rest and, after about 10 minutes, carved into serving trays.