Chickens do not habitually form pair bonds like gunnie fowl but some roosters (sometimes a function of breed) will invest more in care when only one hen involved. Even with more than one hen in a free-range setting, a rooster will sometimes indicate his choices of potential nesting sites, especially with a hen that has yet to pick a nest site. The hen does not always pick same site.
As for rearing together, my games when only a single hen and rooster present, will do so with varying degrees of rooster involvment. Sometimes only helps with predator detection and finding food. Other males will help defend chicks and occassionaly take over caring for brood if hen starts another brood.
