To cook the chicken, preheat the grill to medium. Brush the grill rack liberally with oil and place some aluminium foil on the oven floor to catch any drips. Thread the chicken pieces onto the skewers, spacing them apart so they do not touch. Grill for 6-8 minutes, turning halfway through the cooking time. Then baste the chicken with the butter and grill for another minute, or until slightly charred at the edges and completely cooked through.