Place the chicken breast-side down on a cutting board and use kitchen shears to cut along both sides of the backbone to remove it. Flip the chicken open like a book, locate the breastbone, and press down firmly to flatten the bird.
Pat the chicken dry with paper towels. Season the chicken with the dry rub and salt, if desired. Allow it to rest for 10 minutes.
Preheat the smoker to 225° F(107°C). Don’t forget to stock the hopper with your preferred pellets (we like apple wood pellets for chicken).
Place the chicken on the smoker. Insert a leave-in thermometer into the thickest part of the breast meat, if you have one. Close the lid and let it smoke for about 2 hours, until the internal temperature of the chicken reaches 140° F(60°C).
Open the smoker and brush the chicken with melted butter or olive oil. Turn up the smoker to 300° F(149°C) and continue cooking until the chicken reaches 165° F(74°C).
Remove the chicken from the smoker and let rest for 10 minutes before carving.