I'm pretty sure those birds pair up, on male with one female.That’s interesting I knew roosters didnt sit on eggs, but they should. Eagles do, Bluejays, mockingbirds… hm
With chickens, while the hen is broody, the rooster is still watching over his other hens. So he still has a "job" to do in the flock, even if he is not helping sit on any of the nests.