You may already know all this but I’ll copy something I wrote a long time ago. This is typical mating behavior between mature consenting adults. At 6 months you don’t have that yet.
The rooster dances for a specific hen. He lowers one wing and sort of circles her. This signals his intent.
The hen squats. This gets her body onto the ground so the rooster’s weight goes into the ground through her entire body and not just her legs. That way she can support a much heavier rooster without hurting her legs.
The rooster hops on and grabs the back of her head. The head grab helps him get in the right position to hit the target and helps him to keep his balance, but its major purpose is to tell the hen to raise her tail out of the way to expose the target. A mating will not be successful if she does not raise her tail and expose the target. The head grab is necessary.
The rooster touches vents and hops off. This may be over in the blink of an eye or it may take a few seconds. But when this is over the rooster’s part is done.
The hen then stands up, fluffs up, and shakes. This fluffy shake gets the sperm into a special container inside the hen near where the egg starts its internal journey through her internal egg making factory.
When they are immature but after the hormones hit the cockerels have hormones raging and little self-control. This might start as early as 12 weeks, maybe not until 5 or 6 months. It may be over by 5 or 6 months or it may last several more months. Each chicken is on its own schedule. Those hormones are not primarily about sex at that age, it’s more about flock dominance. The one on bottom is accepting the dominance of the one on top, either willingly or by force.
Each chicken has its own personality, each flock has its own dynamics. In some flocks this is not bad at all, in some it can be painful to watch. The more room they have the less likely this is to be a problem but some have problems even with a huge amount of room.
Male to female ratio can have an effect but it’s not all that conclusive. Some flocks with one male and over 20 females have this kind of problem, some flocks with really small male/female ratios do not. There are a lot of different things involved. Some years I have more of a problem with this than others. The only thing consistent with chickens is that they are inconsistent. We can tell you what might happen but no one can tell you for sure what will happen.
One year I bought 18 cockerel chicks to raise with the flock with five pullets. My cockerel to pullet ratio (considering what I hatched) was absolutely horrible yet I had no problems with over-mated pullets. Some years I’ve had issues when I had several more pullets than cockerels. I always recommend that you keep no more males than you need to so you can meet your goals. That’s not because you are guaranteed to have problems with more males, just that the more males you have the more likely you are to have problems. All you need is one with a personality problem and you have a problem.
Every year I hatch and raise about 40 to 45 chicks, about half are normally cockerels. They are generally raised with the flock. I’m not talking about something I’ve read on the internet, I’m talking about what I’ve seen.
Over-mating can take different forms. Sometimes it can be pretty brutal with pullets being injured. I’ve never seen a pullet injured from mating but some people on this forum I trust say they have. Interaction between cockerels and pullets at this stage can be pretty rough. That’s normal interaction. As long as no one is injured I don’t worry about it.
Our perception can make a big difference in how we think about this. Some people, especially if they are new to chickens, may see one chicken peck another. “Oh, it’s a disaster, it’s an emergency. Call out the National Guard! That chicken is immediately going in time out!” To me that’s how they learn their position in the pecking order.
At this age the pullets are normally behind the cockerels in maturity. The pullets understand the one on top is the dominant one but may not be to the point that they are willing to accept that dominance. That’s understandable, those hormone-driven cockerels can be jerks. So it’s not unusual for the pullets to try to avoid the cockerels. This is one place the more room they have the less problem it is. But even with lots of room the pullets may spend a lot of time in the coop on the roosts where the cockerels can’t get to them very well. I’ve seen this a couple of times, the pullet avoiding the cockerels. The pullets still get enough to eat and drink, when they and the cockerels mature enough (or I put the majority of the cockerels in the freezer) they work it out. Those pullets are not emotionally scarred for life.
Sometimes over-mating can cause the pullet or hen to lose feathers on her back. It’s normal for a pullet or hen to occasionally lose a few feathers from mating, it’s when you get bald patches that it becomes a problem. Before I go further, take a look at your cockerels’ legs. People really get freaked out about spurs. Count how many spurs the cockerel has on its leg and notice how long and sharp that spur is. The look at its claws. Count how many claws it has on each leg and notice how long and sharp they are. Which do you think you have to worry about? Older roosters do develop long sharp spurs, they can be a dangerous weapon. They can cut bare skin if the rooster’s mating technique is not good or he is forcing the hen. But a cockerel at that age? Males stand on the female’s back, what do you think is more likely to remove feathers and cut her back? I know spurs are neat, nifty, sexy, and cool but at six months reality needs to enter the picture.
Some pullets or hens just have brittle feathers, it’s generally genetic. Their body doesn’t absorb or use certain nutrients they need for softer more pliant feathers. No matter how good the male’s technique she is going to lose a lot of feathers. Let’s face it, most cockerels’ techniques aren’t that good, especially when they use force. With their hormones telling them to mate often and the pullets resisting, it is pretty common for the pullets to develop bald spots on their back even with great feathers. I’m not going to downplay the danger, this can get serious if their claws cut the skin. It is certainly something you need to be on the lookout for.
I don’t know if all this typing has helped you or not. Over-mating can occur, it may become serious. Male/female ratio can have an effect but it’s not necessarily as serious as many people would have you believe. As always with chickens the more room you have the better.
Good luck!