Mix one tablespoon salt with one gallon of warm water for the chickens first water of the day, after noon change out water with plain h2o. Repeat every 2 to 3 days until pecking stops. I've done this several times and the pecking usually stops after 2 treatments, this is from a study done in the late 40s and everyone who I tell this to is unwilling to take my advice, hopefully someone takes this advice and spreads it around as it is by far the easiest way to stop pecking in any sized flock