I don't remember if it's on the program The Zoo or The Secret Life of the Zoo, they use a whistle instead of a clicker. A whistle makes more sense to me because it leaves your hands free. It's amazing what they teach those wild animals to do! I guess I lack imagination, it just wouldn't occur to me what things to teach a chicken to do. Open their beak for inspections? Take pills on command? Lay on their backs for belly exams? Oh I know, give me a wing for trims!