One of my 3 hens lays 2 eggs in one day about once a week since I have had them (just over a month, they are about a year and a half old). On her regular laying days She lays her eggs later in the morning than my other two. On the days she lays 2 she lays a hard shelled egg in the morning then a soft shelled egg in the evening. Then the following day I don't get an egg from her at all. I am pretty sure the evening egg is supposed to be for the following morning, but she lays it early. They all eat the same food (laying mash). I don't offer oyster shells in a separate container as it is already in their food. Any suggestions as to why this is happening? Or how to get her to hold it until the next morning?