One of my little Bantams layed her egg out in the run, I went to pick it up and thought it was really light...turned it over there was a hole pecked into it and everything inside either was eaten or drained out.  This is a first for my hens.  I gave them a lecture like a good owner should, then followed it by this threat..."you can always end up as dinner".  They just squawked at me.  Mine get laying feed plus all of the eggshells which I can collect from neighbors into their feed.  I think someone was just having too much fun on the first day of 75 degree weather here in Ohio.
But I always know when a hen lays because the others start making this awful shrill sound and the rooster starts crowing...they are very vocal but I only heard twice today of them doing it and that is why I don't know what happened to egg number three but I do know who layed it....