I have heard that some people have had hens that on occasion lay twice in a day. I have had chickens for forty years and I have never experienced a hen laying two eggs in one day! Yesterday, I found two eggs in the nest! I only have a rooster and hen together in this pen so I know for certain she laid twice. One egg was the normal large blue egg and the other egg was just slightly smaller. Although I was skeptical, I guess it does happen after all.