Are there any other uses for oyster shells other than chickens? I wanted to purchase some at the feed store and I have to buy 50lbs for say $13. I can order smaller amounts on the web but once you add shipping, it costs the same. With my 7 hens it would take a life time to use 50lbs and in that time most would be wasted. I have tried baking egg shells, then grinding them up and they won't touch them. Anyone have some ideas? John