Nesting, but no egg?

[EssexGirl]

One of my hens, a Mottled Java who's probably just about a year old, frequently sits in the nest box for half an hour then flies out squawking, but hasn't laid an egg. She is laying, but not every day. Anyone know why she would do this?

 

[Luke13:34]

I don't have an answer.. but I have an EE who also likes to nest and sing the Egg Song without actually producing an egg. I'll add another

.

 

[EssexGirl]

Maybe it's just that her timing is off ... she went back later in the morning and laid an egg!