Ok so I might have worded it wrong the chicks from the hatchery get here April 15. But if I let my chicken sit on eggs they won't hatch until a week after my hatchery chicks arrive.
Let her set on fake eggs, not real ones....then pull the fakes and replace with the day old chicks when you get them.
A hen doesn't really care if she is on real or fake eggs, she just wants to sit on something...