My birds have taken it upon themselves to eat the laid eggs. I collect the eggs every evening and was averaging about eleven. That suddenly dropped to four or five. When we cleaned the coup out (do it about once a week) one hen was attacking the already laid eggs. She would break the shell and eat our the yolk. We had to do battle with are to keep her out of the way while we cleaned. We noticed that the other hens would take the broken shells and eat the whites out of them. What the heck caused this? How do you stop this?