Garydean was right about broodys in with the flock. they were running around fighting over a premature chick. another egg in the nest was cracked open like they were eating it out of the shell. last time I was able to count there was 18 eggs +. after this incident only 12 were left.
I'm really sorry to hear this.
Lat year I had a broody in the main coop. I got worried about just this sort of thing so I put up a wire mesh screen between the nest and the flock so they could see each other bit they wouldn't disturb the broody. I was afraid if I moved the whole nest I would break her (its happened before in the not-so-serious broody) but I didn't want the mean girls attacking the little ones.
Was this the nest with the multiple broodies in it?