A quick note if you're performing this method on turkey: Turkeys are larger birds, so they'll take a little more muscle to break down. Remember to have your turkey completely dethawed by the time you begin to prep it. A frozen or partially frozen turkey will be very difficult to spatchcock.
Turn whole chicken or turkey breast-side down on your cutting board.
Using your hand, pull up on the neck to reveal the natural cut line on either side of the backbone.
With a very sharp knife, cut along both sides of the backbone from head to tail and remove. This will be a bit more work with the turkey.
Turn your chicken or turkey over so that it is breast-side up.
When spatchcocking a turkey you may need to notch the “V” bone at the top of the breast bone to weaken it and make it easier to break.
To break the breastbone of the chicken, push down on the breastbone with your palms. For the turkey, use a heavy knife or cleaver to help make the break. You should now be able to lay your chicken or turkey out flat.
Rub the inside and the outside of your chicken or turkey with vegetable oil, gently working your fingers under the skin. Try to only create one small hole in the skin on each breast and in the legs through which to apply oil and rub. You want to keep the skin attached as much as possible to retain moisture.
Apply your favorite dry rub to both sides of the bird and shake onto your fingers to work up under the skin.
Put turkey into smoker and cook at 275F – 300F until breast temperature reads 165F and thighs are at 180F. When done, the legs should turn easily and the juices should run clear when the flesh is punctured. Cooking times will vary based on the size of your bird, but you’ll probably be at about 6-7 hours for a 12 lb turkey.