Preheat your broiler or grill. In a large bowl, combine all ingredients except butter and hamburger buns.
Form chicken mixture into 4 patties and place on greased broiler pan or grill. Broil or grill burgers for 4-6 minutes on each side or until the internal temperature reaches 160 degrees. Spread butter on the insides of the hamburger buns. Place on broiler pan and broil for a few minutes until golden brown. Serve burgers on toasted buns and top with additional ranch dressing.