My cochin layed a double hard shell it cracked in the bator and there was another shell it cracked but all goo in side. .. was I seeing right. all that was there was a double layer of shell why did this happend.anyone have an answer.. could it be too much calicum?? they are raised on purina laylena. and a few veggis once in a while and yogurt and milk no fat.once a month.