The biggest problem with smoking duck is dealing with the fat. Water birds have a lot of fat that has a strong flavor and won't melt away easily. Now a general rule of smoking is that fats liquify and render from meats. This isn't true of duck.
There are however a few things you can do to help render the fat and maintain the flavor. The first rule should be to smoke ducks breast side up. This helps drain the fat away from the breasts. You can also pierce the skin in several places making it easier for the fat to drain out. The skin of ducks is designed to be very insulative and makes it so that fat can't escape. You may also wish to smoke water fowl longer than you would something like chicken. This will also reduce the amount of retained fat.
Another way to prepare duck for the smoker is to use a brine. By placing a duck in a brine overnight you will tenderize the meat and add in the rendering of the fat. Typically a brine can be as simple as 1 to 2 cups of iodine free salt in a gallon of water to the flavor enhancing recipes.
A third way to prepare duck is to steam it first. This method works particularly well for duck that has been cut into pieces. For a couple of duck breasts you would want to steam them for about 20-30 minutes and then smoke for about 2 hours.
The last method would be to smoke ducks for a very long time at about 180-200 degrees. I mean we are talking about 6 hours or more. This will allow enough time for the stubborn fat to break down and drain away.
Remember, no matter which method you use. Poultry isn't cooked until the center of the thickest part reaches a temperature of 160 degrees.
