To make in a crock pot, follow directions below but in a crock pot instead of the oven. Set on low and cook for 8 to 10 hours.
Preheat oven to 400 degrees. Make a BBQ sauce by mixing Black Hills with ketchup. Mash achiote paste into BBQ sauce until thoroughly combined. Place in a Dutch oven or casserole dish and spread sauce over all sides of meat. Squeeze orange juice and pulp over meat and pour in remaining ingredients. Cover and place in oven, cook for 40 min., remove cover and cook for 10 more min.
To make a nice serving sauce, pour 1 cup of the liquid from the cooked barbacoa into a saucepan. Over medium-high heat, stir until reduced to a thick sauce, about 10 to 12 min. Try serving barbacoa on tortillas, sprinkled with your favorite shredded cheese and topped with a spoonful of this tasty sauce.