Start by trimming any excess skin/fat from the meat and then rinsing it off. Tap dry to remove excess moisture and prep for the rub. Sprinkle about 1/2 tablespoon per thigh of spice, making sure it's on both the front and the back, and rub it into the chicken really well. Once all the chicken is rubbed, place it into a 9x13 oven safe pan, cover it and return it to the fridge. You want the meat to be as cold as it can when placed in the smoker.
Turn your smoker on to 250 degrees and wait until preheated.
Once your smoker is up to temperature, remove the chicken from the fridge and top each chichen breast with a dollop of butter. Place the whole pan of chicken onto the grill of your smoker and let cook for 1 hour
After 1 hour, place foil on top of the pan, and cook for another 1 hour
Prep the BBQ sauce in a large bowl, big enough to dunk the chicken into. Remove the chicken from the smoker and using a pair of tongs, one by one dunk the chicken thighs into the BBQ, coating both sides. Place each chicken onto a flat cooking sheet that will fit inside your smoker.
Return the chicken to the smoker to cook, uncovered, for an additional 20 minutes or until the internal temperature reaches 165 degrees.
Remove the chicken from the smoker, cover with foil and let it rest for 10 minutes before serving.