Wc, all eggs have the blastodisc on them, the white spot, but not the circle around it. An infertile egg does not usually have that white circle around it. That is the way you tell a fertile egg from an infertile egg. I don't know why an infertile egg would appear to be fertile; perhaps there is an explanation, however, that picture shows what appears to be a fertile egg. http://www.hatcheryoffice.com/embryology/determfert.htm