I was feeding egg shells to my girls. I saw in a post you should feed crushed oyster shells so I switched and stopped the egg shells. Well, now they are eating eggs. they actually fought over the shell not the egg. Are they deficient in something? I guess the egg shells are back on the menu with the oyster shells but they won't touch them the feeder is still completely full. They are 11 mos old and are eating dumor layer feed 16. Any suggestions?