Sometimes, if there's no cockerel, a bossier hen will assume the role, even being the first to leap to the defence of the brood at great personal risk. If a cockerel is subsequently introduced, a period of adjustment to the pecking order follows. A good cockerel enjoys droit de seigneur (frequently) but is a fierce and brave protector of the flock, putting himself between the threat and the hens, defending to the death if necessary. When tasty food is served he waits courteously for the hens to have their fill. A diffident cockerel is cold-shouldered by the hens.
It would be so fun (and clearly enlightening) to have chickens in the city! They remind me tiny T-Rexes!