I have a hen that has consistently laid a very soft shelled egg or no shell at all. I've put several dishes out with oyster shell and even put a little in their food. This has been going on for over 2 yr. What a mess every night. The other girls can't lay their eggs in another nest, they have to all lay in the same one There are only 5 hens in this coop. Have you ever separated them to see who is laying what egg? If any of these 5 get separated from each other they go nuts. I guess I'll see how it goes.