We don't need you specific location, but knowing what state helps by letting us know your climate at this time of year. What I have in Michigan is waaaay different from someone in Florida, for example, and people would suggest different things.
When you buy chicks, they are designated as "pullets," ie, girls, or "straight run," which means they could be either sex. If there was no designation, assume straight run.
When they sex birds as chicks, they do what's called "vent sexing," and separate the boys and girls. The problem is, vent sexing is about 90% accurate, so you can still end up with cockerels. Sounds like you know you have all pullets, so that is a good thing.
If my math is correct, you have 11 birds, correct? 81 square feet in your coop should be enough, and it sounds like you have a big run. Perhaps try letting them out together, under supervision, in the run, where there is plenty of space for the younger birds to get away. Places for them to hide behind or under things can help a lot, as long as it's not a dead end where they can get trapped.
As mcdze said, have several feeders and waterers, so the older birds can't keep the new ones away from food and water.