Hello, So, some of my hens have been laying super thin shelled eggs. Some hens haven't even been laying. I don't care a bit about the eggs, but I do care that my hens aren't getting enough calcium. They eat layer pellets. I give them oyster shell mixed with scratch, but they always eat the scratch and leave the oyster shell, no matter how well I mix them together.. So, are there any foods that chickens like that would be a good source of calcium? Thanks!