ok, "food" for thought. I give them their eggshells, dried and crushed but not cooked or anything. It does make sense about nest cleaning and such. Thanks.Nope....just a myth. Chickens have been eating their own eggs since the beginning of time and out of necessity~to keep their nests clean. When an egg gets broken or cracked enough to leak into the nest it can cause bacteria growth there and even attract predators, so eating their own eggs is not only instinctive for an omnivorous creature, but also serves to protect them and their nest.
This will not cause them to cannibalize all their eggs nor produce dedicated egg eaters...or their specie would have died out long, long ago. I've been feeding raw eggs and their own egg shells back to them for 40 yrs and never had a dedicated egg eater in any of my flocks....and that's hundreds of birds over that length of time.
It's just a misguided notion to imagine that eggs and egg shells need to be cooked and altered in order to serve them back to the flock.
--V