While the sauce is simmering, season the chicken on all sides with salt and pepper. Heat olive oil in a large cast-iron skillet. Sear the chicken on all sides until golden brown. Remove the chicken from the skillet and place in the crock pot.
Pour the BBQ sauce over the chcken. Turn the chicken so that it's coated with the sauce. Place lid on the crock pot. Cook on LOW for 6-7 hours or HIGH for 3-4 hours.
Transfer the chicken to a serving platter and sprinkle with fresh parsley.