The night before: Mix together 4 cups of apple cider or apple juice with 1/4 cup of salt. Stir until the salt dissolves.
Wash the chicken, removing the giblets, then pour the brine over the chicken and refrigerate. Turn occasionally.
To prepare: Spray the inside of a 6 quart slow cooker with cooking spray and set on low. Remove the chicken from the brine, and pat dry.
Mix together 2 tablespoons of applewood rub, two cloves of minced garlic and 4 tablespoons of butter. Rub all over the chicken. Loosen the skin around the breast and leg portions and tuck some of the mixture under the skin, too.
Sprinkle the top with additional seasoning and center in your slow cooker.
Pour 1 cup of apple cider or apple juice around the chicken and place the lid firmly on top.
Cook on low for 6 hours then check for doneness. Depending on how your slow cooker cooks, and the size of the chicken, it may take a little longer likewise if smaller less cooking time.
To crisp the skin, carefully move to a baking pan. Broil, in the oven for 3-5 minutes until the skin is crispy and golden.
Allow to rest for 10 minutes before carving Drizzle with the pan juices just before serving.