We have five hens and four nest boxes. Everyone is free-ranged and is generally on their best behavior except for laying time in the morning, when the coop turns into a mental institution as soon as more than one of them at a time wants to lay. If one is already in a nest box, 1-2 others will often come in and start complaining (egg song) non-stop for up to an hour. There's even one that doesn't lay too often who will stand there and complain even when she has nothing to lay that day. It's a fair amount of racket to be sure.
Is this common or is there something in our water supply? :-)