I too found a rubber egg today. Not in the nesting box but in the litter in the hen house. I am not sure when it was laid. I am assuming that it may have been yesterday because it was covered with ants. Then today I had a new egg, different than all the others. I have six hens and I had suspected that one was not laying yet as all the others seem similar....yet different from each other. Today's new egg was slightly more yellowish brown and speckled. So far i have never has 6 eggs in one day. When that happens I will know they are all making me proud. So glad you have posted your experiences as well as this is so helpful.