Egg song = start of egg laying

[Hatching]

i have a small flock of 8 pullets ( 15, almost 16 weeks old) and for the past three days one of the barnevelder pullets has been singing an egg song. I have had hens before and know the difference between an egg song and a scared chicken alarm. I go out to see if there's an egg and everytime she's just on the perches in the coop singing or strutting inside the coop. Do you think she will start laying soon? I thought 16 weeks would be a little young for a barnevelder, and I would have thought that the hamburg would have started first.