First a little background. A) We have a lot of snails here. My chickens are allowed to free-range in our little backyard during the day and they're very good at finding all the snail hiding spots. I'll frequently find them hiding behind a perennial bashing a snail against concrete or a rock to break it open but they also end up eating the shell. B) This spring while cleaning out the garage I found an amazing cache of empty snail shells left by rats. They had been taking them behind some old railroad ties where they ate them and dumped the shells in a big pile. There have to be at least 200-300 large snail shells back there, the size you see in a restaurant when you order escargot. C) I'm extremely thrifty. Or cheap, depending on who you ask. So taking these three things into account, could I get away with feeding my two hens crushed snail shells (as well as cooked crushed egg shells) instead of buying oyster shells to supplement their calcium? I really hate buying something if I have a good FREE alternative. So far we've been getting eggs for a little over a month and the shells seem very thick when I break them to cook. Please reassure me that I can continue not buying expensive oyster shell.