Originally Posted by Kino
Does she receive enough protein in her food? Do you use pellets? Some weak shelled eggs can be caused by lack of protein.
I don't think protein makes for stronger shells......calcium does.
This bird could just have a glitchy shell gland....if your other birds are laying 'good' eggs, your nutrition regime is probably fine.
She may not be assimilating nutrients properly, usually a genetic thing and not much you can do about it.
As to why she's not molted I'm not sure, unless she is not as old as the others?
Could also be a genetic glitch.
Not all birds molt at the same time of year, especially if you are using supplemental lighting for winter laying.