Shake Shack offers a Chicken Shack Sandwich for Free when you Spend $10 or More and apply promo code CHICKENSUNDAY via Mobile Order (iOS or Android), Online or in-Shack through a kiosk.

Note, valid at participating locations on 4/7, 4/14, 4/21 & 4/28. Order total must include a minimum of $10 worth of food or beverage products. Must add at least (1) Chicken Shack (max savings of $9.79) to cart prior to checkout.