Go to this link to see what i did to solve my egg-eating hen problem:
Thank you so much, mustard didnt work for us either! we ended up purchasing ceramic eggs, FINALLY did the job all around!
Thanks again for sharing!
I'm not 100% sure on this, but this is what I understand:
Chickens, hens and roosters alike, generally shouldn't eat their own eggs. It's detrimental to whoever's collecting the eggs, it causes strife between chickens, and is really weird in general.
Most of the time, the first egg is broken in the nest by mistake. Maybe the hen is heavier than most others, or the egg rolls out and breaks. Either way, the hen decides to try it and it, being a delicious egg (even in its raw form), is liked by the hen. She'll continue to break and eat eggs, because, if you routinely pooped out eggs, wouldn't you?
The thread itself contains information on how to prevent it. Luckily, I haven't had this issue with my seven hens and hopefully I never will. :)