Prepare the smoker by soaking wood chips in water for at least 2 hours. This prevents excessive burning and creates better smoke flavor. Reserve the soaked chips until ready to use.

Remove the whole chicken from the refrigerator 30 minutes before cooking. Room-temperature chicken cooks more evenly. Pat completely dry inside and out using paper towels—this ensures crispy skin, about 5 minutes of work.

Mix the dry rub by combining 3 tablespoons kosher salt, 2 tablespoons black pepper, 2 tablespoons garlic powder, 2 tablespoons onion powder, 1 tablespoon paprika, 1 tablespoon brown sugar, 1 tablespoon dried thyme, 1 tablespoon dried rosemary, and 2 teaspoons cayenne pepper in a small bowl. Stir until evenly combined, about 1 minute. Checkpoint: All spices should be fully blended with no clumps.

Combine 2 tablespoons softened butter with 1 tablespoon minced fresh garlic in a small bowl, stirring until smooth, about 1 minute.

Carefully lift the chicken skin on the breasts and thighs without tearing it. Spread the garlic butter under the skin, directly on the meat, covering as much area as possible. This adds flavor and moisture to the inside, taking about 3-4 minutes total.

Apply the dry rub all over the outside of the chicken, pressing firmly so it adheres to the skin. Don't be shy—cover every surface evenly. This takes about 3-4 minutes. Rub some of the mixture inside the cavity as well.

Stuff the cavity with: 1 lemon halved, 1 small onion halved, and 4 sprigs of fresh rosemary. These aromatics release steam and flavor during smoking, about 2 minutes.

Preheat your smoker to exactly 225°F (107°C) for 20-30 minutes. Check the temperature with a reliable thermometer placed at grate level where the chicken will sit. Maintain 225°F throughout cooking. If using a charcoal smoker, this may require adjusting vents; if using a gas or pellet smoker, adjust heat settings.

Fill a disposable drip pan with 2 cups chicken broth. This pan will catch drippings and create humidity inside the smoker, preventing the chicken from drying out. Place this pan directly below the chicken grate.

Drain the soaked wood chips and add them to the firebox or smoker's smoking chamber according to your smoker type. If using a tube smoker or smoke box, add chips directly. If using offset firebox smoker, add to the coals. You should see thin, white smoke beginning to rise within 2-3 minutes. Checkpoint: Smoke should be thin and wispy, not thick and billowing.

Place the chicken on the smoker grate breast-side up, directly above the drip pan. Position it so it's centered on the grate and not touching the smoker walls. Close the smoker door/lid.

Smoke at 225°F (107°C) for 3 to 3.5 hours total. Do NOT open the smoker frequently, as this drops temperature and extends cooking time. For a 5-pound chicken, plan on roughly 35-40 minutes per pound. Check the internal temperature ONLY after 2.5 hours using an instant-read meat thermometer inserted into the thickest part of the thigh without touching bone. It should reach 165°F (74°C). If not there yet, check again every 15-20 minutes until target temp is reached. Checkpoint: Thigh temperature must be 165°F (74°C); breasts can be 160°F (71°C) and will carryover cook.

When the chicken reaches 165°F (74°C) in the thigh, remove it from the smoker using tongs or a poultry lifter. The skin should be deep golden brown, almost mahogany in color, and pulling away slightly from the legs.

Tent the smoked chicken loosely with aluminum foil (not wrapped tightly) and let it rest on a cutting board for 10 minutes. This allows juices to redistribute through the meat. Do not skip this step. Checkpoint: Chicken should still feel hot and steam should rise from under the foil.

After resting, transfer to a serving platter or cutting board. If desired, carve into breasts, thighs, drumsticks, and wings, or serve whole. The skin should be crispy and the meat should pull away easily from the bone.

Drizzle any accumulated pan drippings from the smoker's drip pan over the carved chicken for extra flavor. Serve hot or at room temperature.