People want hard and fast definitive answers to these questions but real life doesn't work that way. Each chicken is an individual and each flock has its own dynamics. Those dynamics can change as the chickens mature or if you add or subtract chickens. If you read through the posts on this thread you'll see that different people get different results. I get different results myself. It's not unusual for me to see three hens in one of my nests at the same time while all other nests are empty. I used to have a hen that would not allow another hen in the nest with her and she'd take three hours to lay her egg. I saw one hen walk up to a nest, grab a hen in the nest laying an egg buy the head, and jerk her out so she could lay her egg in that nest. I see all kinds of different behaviors. Most of mine are quite willing to share but some are not.
If I get seven eggs in a day four might be in one nest, two in another, and one all alone in a third nest. A couple of weeks later I might see the same distribution but in different nests. A nest that is empty one day may have three eggs in it the next.
We can't give definite answers to these questions. The best we can do is to use rules of thumb, numbers that usually work. In some cases they are overkill, they don't need that many nests. In some cases it may not be enough, say you get two hens like those I had, but usually if you go by the rules of thumb they will be.
