I can't find any vids of our girls clucking each other (I'll try to remember to film one tonight). Are you talking about the way Amelia is sassing Angus at the start of this video? The "cluck-cluck-cluck" and the side-to-side head action is pretty similar.
I think you may be referring to the bossy "Cluck-cluck-cluck" our girls do when they are sassing each other. If so, it's a pecking order. Let me see if I can find a video.