Is it possible to already have a fertile egg with only one day with rooster. I saw him holding her down, but not sure if he actually did his job. I understand a fertile egg will have a bullseye. I have a egg with a white center, then a shade of lighter white surrounding the center. Is this fertile ? Or should there be a ring around this? To me it looks like a bullseye, and it hard for me to believe it's fertilize with only day together?! Just a post note, this is also a larger egg than she usually lays.