So I've noticed if the chickens get into the trash they fight over the egg shell and then yesterday when I dumped the duck water there was a broken duck egg- I hosed down the yolk so they wouldn't eat it but left the shell and it became a feeding frenzy. The duck was eating it then one chicken took it from her mouth and another chicken stole it from her. They were like sharks. Is this normal? Are they low in some mineral? Calcium? I feed them layer pellets and try always get table scraps and scratch grains and they are free range so whatever bugs/plants They find.