Hi all. Do you guys regularly offer oyster shell? I've left it out two or three times, but it eventually gets knocked over when someone tries to scratch it, and it winds up on the ground. For some reason they don't really like to eat it off the ground like they will scratch. Go figure. Anywho, if you do leave it out, how do you so that it doesn't get turned over? Just curious. I've been giving them finely-crushed egg shells, and those seem to be disappearing, and we haven't had any soft shells yet, except for one "first egg" incident, but I have to figure that at some point they're going to need some extra calcium. Thanks!