LOL, there is a VERY good chance then that they are fertile..
We eat a lot of eggs so when our roo started doing his job we were able to verify seeing the fertile egg..
check them in 7 days of incubation, some of mine are white shells and I can see the veining start by day 4
White shells are easy to see, however I have all brown egg layers, and most lay really dark eggs, so its harder for us to even candle them. We tried that last year and it wasn't easy at all. This is why I watch my rooster. Normally you can hear all of them out there. Last year I had 1 rooster for every 4 girls this year I have 1 rooster for 2 Delawares, 1 rooster for my little GLW, and 1 rooster for 7 girls, he has 9 now but will be losing 2 tomorrow when I move them to the Delaware cage. My boys keep busy.
I have one Rhode Island Red hen that all of my boys love. My main rooster doesn't go nuts with her but my white boy he will breed her 20 times a day if I would let him. I have to separate her from the Delaware every time.