Wash birds inside and out., Put water in a large non- aluminum container, add salt and sugar and stir to dissolve. Add soy sauce, tarragon, thyme and pepper. Submerge birds in brine and weigh them down with a heavy plate so that they stay submerged. Refrigerate overnight.
Remove birds from brine and wash inside and out. Pat dry. Reserve brine. Start smoker, fill water pan with water and half of reserved brine.
Place chickens, breast side up, on top rack of smoker. Cover and smoke at 200 to 250F for approximately four hours, until internal temperature of the thickest part of the thigh reaches 170F. Baste with olive oil after two hours.
2 chickens -- (3 1/2 lb. each)
1 gallon water
3/4 cup salt
2/3 cup sugar
3/4 cup soy sauce
1 teaspoon each dried tarragon, thyme, black pepper
1/4 cup olive oil