Have a single rooster with 4 hens in established flock. Am now adding 16, yes 16 new young hens. These new girls are still pretty young at just 6 weeks
In my flock a dominant rooster considers chicks to be his as long as they aren't old enough to be rivals. Some help take care of the chicks but most just leave them alone. I like having a dominant rooster in the flock when I integrate chicks.
but I expect one day soon the rooster will realize they are hens.
One day they will be hens. A good rooster doesn't try to mate with immature pullets, but not all mature roosters are good. Still, with most this isn't a problem. I think how much room you have makes a difference. With my flock the immature chickens (male and female) form a sub-flock and avoid the adults until the cockerels hit puberty. That interaction can get exciting. But the pullets stay away from the adults until they mature enough to join the pecking order, which is usually about the time they start to lay.
You may notice that most of the horror stories on here involve immature cockerels. Mature roosters are generally much better behaved. But not all roosters are good.
There are always exceptions to any behaviors with living animals. You never know for sure how any one animal will react in a situation. Generally the more tightly they are squeezed together the more bad behaviors are magnified and the more likely you are to have bad behaviors.
Just curious: what are the cues that help a rooster ID a hen? Pheromones, maybe? Long eyelashes?
Good question, I don't know all the answers. Typically a pullet or hen that is laying or is about ready to lay will have bright red combs and wattles. Not all do but it is pretty common. That bright red is a signal to the rooster that her eggs probably should be fertilized. There are probably other signals, physical or behavioral, that he recognizes but I don't know what they are. There must be because other boys usually have bright red combs and wattles and most roosters leave them alone.
The mating act is often about dominance much more that fertilizing eggs. Immature cockerels seem to want to mate everything when those hormones hit. They are trying to establish dominance. They are so hyped up on hormones rational behavior is out of the window. Once they mature enough to get control they often settle into a good adult, but as someone I miss on here once said, watching juveniles go through puberty is often not for the faint of heart.
In an all-girl flock the dominant hen may mate with another. She's not kinky, she is showing her dominance. I've seen that when an immature cockerel was in the flock, she mated another hen in front of him just to show she was the boss. The same type of thing can happen between boys, just showing dominance.
Chicken society can be pretty complex. We will never understand all or probaby most of it. Individual personality, room, flock make-up, and our management techniques contribute to that too.