The correct answer is "brailing." Brailing is a process used to prevent birds from flying. It involves clipping the primary flight feathers of birds to prevent them from taking flight. This procedure is commonly done to domestic birds, such as chickens or ducks, to keep them confined to a specific area or prevent them from escaping. Brailing does not cause any harm or pain to the birds, as it only trims a small portion of their feathers. Debeaking, on the other hand, is a process that involves removing or blunting the beak of a bird to prevent pecking, while dubbing involves cutting or removing the comb or wattles of a bird for various reasons. Pecking refers to the behavior of birds pecking at objects or each other and is not related to preventing their flight.