Is there a trick to finding out who is breaking/eating eggs?

[Love my Critters!]

One or some of my EEs are breaking and eating eggs. I can't figure out who it is. I do not have a way to separate them individually either. I was wondering if anyone knew of any "tricks" to help me figure this out.
Thanks!

 

[HHandbasket]

Yes, there is a pretty easy way to do it. Get a fresh egg and poke out the ends and blow out the contents so that it's hollow. Fill the egg with mustard and put it back in the nest. Who ever comes out with mustard face is your culprit.

 

[Love my Critters!]

Great Idea, I'm going to try that! There are 4 nest boxes but they all use the same one and sometimes several of my hens are in it at the same time