Linking in from Dave's post about unfertilised chicken eggs and caviar, can someone please explain to me how and why chickens lay unfertilised eggs? (There was a recent thing in the British press about a young girl hatching two ducklings from organic eggs).
Why do they go all the way through the energy requirements for producing an egg and coating it with a shell (using the calcium and phosphate resources from their own body to do so) when there is no end product?? To do so is deleterious to the chicken with no gain.
Is there something ridiculously fundamental I'm overlooking??