Hi I have a friend who says I should feed oyster shells to my hens, but Poulin says that their Layer pellets have enough calcium that a supplement isn't necessary (it contains between 3.75 % and 4.5% calcium). I boiled leftover eggshells and crushed them, and the hens ignored them, so I'm reluctant to buy a bag of oyster shells if the same thing is going to happen. (I'm out of work right now) Is there a chart of nutrient requirements somewhere that I can't find through google (I've tried)? Thanks in advance for the help! Oh if you need to know, I have two 1-yr old Americaunas: Fifi LaBrunch and Babs, and their shells are nice.