My peahen, Hannah, has laid several eggs that had very thin shells and broke. This is her first year laying. She has plenty of oyster shell available for calcium but her egg shells are very thin and will break in your hand when you pick them up, or are already broken in the nest when you go to collect them. Her sister peahen, Bella, is also in her first year of laying but has good strong shelled eggs. Any ideas what is happening with Hannah?