If you have quite a few chickens you might notice a behaviour during egg laying time. This can be the cause of many noisy backyard flocks.
Many think that she is just waiting for her favourite nesting box to become available, but in actual fact she is acting as encouragement. Quite often the sitting hens will respond to her and it can become quite noisy during laying time.
Some breeds can be much noisier and encouraging than others.
The more hens you have, the more obvious this behaviour will become, as well as frequency during daylight hours.
This is normal behaviour.
You can encourage them to keep a little more quiet by going into the shed. This alone often helps to calm the situation down.