I have a Plymouth Barred Rock rooster who got aggressive when I tried to move a hen who had gotten into the wrong pen back into her pen. He came at me in full attack-mode, but I calmly put my hand on his back and held him down for a few seconds. Since then, none of the roosters (we have 3) have made any move to be aggressive towards me when I am in their pen. They get riled up if we have an escapee hen, but quickly calm down when I return the hen to their pen. They seem to know that I am the "dominant" being in our barnyard. We also have a shepherd-mix dog who won't back down when we need help corralling the chickens, and they respect her just as much!