Weird egg song?

[RAsChickens]

So today I was out volunteering at a nearby school. When I got home, my boyfriend said our 5 18 week olds had sung the egg song! I grabbed my laptop, went on YouTube, and played a video of the egg song. I said "did it sound like this?". He said "Exactly like that!". So we went outside and checked everywhere, but couldn't find an egg! Is it normal for hens getting ready to lay to sing the egg song? Or was this a sign of something else? I'll put the link to the video I found below, the one my boyfriend said sounded exactly like what they were doing.

Link:

 

[rosemarythyme]

Some of mine sing it at random (they'll sing for someone else laying, or for no reason at all). Maybe they just like to see me come running in to check the nest box or something.

 

[Abriana]

Sometimes my hens, who have been laying for a little less than a year, do an egg song even if they are not laying an egg. My hen Christina clucks her head off anytime she wants. I even heard a chicken doing it last night on the roosting bars. They are probably getting ready to lay. keep checking the nesting boxes!

 

[aart]

That vocalization is not always immediately accompanied by an egg.
An alarm call can sound very much the same....or they are just yelling for who knows what reason.

Tho your birds may be getting close to point of lay, thus it might be part of the hormonal surge that precedes the onset of lay. Last year my pullets made an ungodly racket all day long for weeks before and while beginning to lay. It was crazy!