Besides giving chickens oyster shell, is there any other options? We have 6 laying hens, and also, 3 laying duck hens. I have one or 2 (I suspect) Wyandotte(s) who seem to lay a very thin shell once in a while. Enough that it's making a difference in how long they last! I had some eggs in the fridge (that were once on the counter), that I sorted, that went bad. They were all from Wyandottes. (I have Ameraucanas also) The eggs that were the thinnest were DISGUSTING!! Is it something they are not getting, or is it just them?? The other eggs are fine. I also feed them back their shells too. They eat Purina Layena, and they also free range. Thanks.