Take the giblets and any packaging out of the chicken cavity and throw them away. Pat the bird dry with paper towels so the seasoning sticks better. This takes about two minutes and sets you up for a juicier result.
Dice the carrots, onion, and celery into small, even pieces. Spread them across the bottom of the slow cooker in a single layer. They act like a flavorful rack and later become part of the stuffing.
Set the chicken on top of the vegetables, breast side up. Pour the melted butter over the whole bird. Sprinkle on the thyme, sage, paprika, salt, and pepper, covering the top and sides.
Cover the slow cooker and cook on low for 7 to 8 hours, or on high for 4 to 5 hours. The chicken is ready when the juices run clear and the meat is tender. Try not to lift the lid, because every peek lets heat escape.
Carefully move the chicken to a platter and cover it loosely with foil. Use two large spoons or tongs, because the bird will be very tender. Resting keeps the juices in the meat so every slice stays moist.
Pour off most of the liquid from the slow cooker, leaving 1.5 cups behind with the vegetables. Save the extra liquid for gravy or another meal. Matching the liquid to the stuffing box directions is the most important step in this recipe.
Pour the dry stuffing mix right into the vegetables and the 1.5 cups of liquid. Give it one gentle stir so everything is moistened. Put the lid back on and let it sit for 10 minutes.
Fluff the stuffing with a fork until it looks light and fluffy. You can put the chicken back into the slow cooker for a cozy presentation. Or carve it on the platter and scoop the stuffing alongside.