My husband saved all the oyster shells and the body shells from the crabs that we ate for Christmas dinner. I have three dozen oyster shells and 6 crab shells. If I put the oysters in a fabric bag and send my 9 year old little guy out with a hammer, do you think my hens will eat this crushed shell?? This sounds like I could be both "recycling" and creating a FUN project for my son (a hammer is a boy's best friend right?) What about the crab shells...anyone ever fed those to a hen?