I have a girl laying thin shelled eggs. Now I know what you are all thinking, put out oyster shells etc. We've done all that. She has free choice oyster shells, eats Purina Layena crumbles. Hasn't had too many treats lately and still the shells are very thin. The other girls shells are so thick I nearly need a nut cracker. Any ideas what I can do for this girl to get her laying better eggs? I'm not even sure which girl it is. How in the heck does speckledhen know who's eggs are who's? I can't even tell my girls apart.