I just found 12 eggs in a hidden nest, and I have a very small urban yard!! I'm going to test them out and see if they're ok. This is not based on knowledge, I think they just announce that they laid and before I think it's a squabble over who is going to lay!
Egg song is a genetic trait that goes back to the jungle fowl. While foraging, a hen will go back to lay in the nest while the others continue to forage. When she's done, she will call out "hey, where are you guys". The flock will call back "here we are." Even if they're all in the same pen/building they still do it. I've even heard the song from roosters that were out of eyesight of the flock.
