Two of my three pullets have started to lay. Both have only laid soft shelled eggs so far...two or three each. All but one have been broken in the coop or nesting box. At first, i thought that they were broken because they were so delicate. This morning however, the "egg" I found was destroyed. I dont know if the contents were eaten...i can't really tell. Obviously, i dont want my chickens to get in the habit of eating their eggs. I'm giving them oyster shell and layer feed to strengthen their shells. How long does it take to "work"? Should i do anything in the meantime?