Angel Wing, also called Slipped Wing, is a disease affecting ducks and geese. Usually acquired in young birds, the disease turns into an incurable condition. These waterfowl acquires this disease when given a high protein diet with low in manganese and Vitamins D & E. It can affect one wing, usually the left one, or both wings.

Young birds are treated by wrapping up the wing/s and binding it against their flanks. By adding a more healthy diet after treatment reverses the damage caused by this condition. However, adults birds that acquire this condition usually die as they become completely incapable of flying.

Angel wing symptoms include stripped feathers in the wrists and remiges that protrude from wings at noticeably odd angles. Rare cases may resemble the stripped feathers as blue straw.

Angel Wing is theoretically caused by excessive protein or sugar consumption. Some experts also believe that this condition is genetic.