I have ten 7 month old chickens. One or two of them are regularly laying eggs without the hard shell. The eggs just have in inner membrane holding them together. All of the chickens are eating the same feed- an organic feed from Purina along with oyster shells. I originally thought that this was from new chickens laying their first eggs and that the issue would go away. But two chickens continue to lay these eggs after more than 3 weeks. And they are laying these eggs during the night while they are on the roost sometime before 5 am. I find the eggs on the coop floor, sometimes they break open. I have to clean them up before the chickens get off their roosts. I think I have finally identified the two chickens who are doing this. Any ideas about the cause and if there is a cure for this?