We learn a lot from the birds at the farm. My friends in the non-profit world have come to respect the wisdom, like; "Stressed hens don't lay", and "Leave the Broody Hen's eggs in the nest", and of course, "Broody Hens mean Baby Chicks". See when a hen insists on staying on her eggs, and she has plucked out some breast feathers to keep them warm, she is indicating that she is raising babies. In 21(ish) days there will be new chicks peeping out under these birds.
It looks like there are more broody hens than clutches of eggs to go around in this nesting box. Oh well, there should be plenty of parents to help when the babies are born. Watch this space!