You'd be surprised at how much "energy" those roosters can have. My younger rooster can easily service 10 hens in one evening. Considering they are fertile for two or more weeks after being with the rooster he could potentially produce chicks with many hens. However, I have hens that just don't like him and steer clear. He ends up hooking up with the same hens day after day.
Now I have a new rooster that is a few months older than the other one. The hens that don't like the first rooster seem to fancy the second one. The first roo is out of commission for a while and the new rooster is taking care of almost two dozen hens. I hope you get a good hatch rate with your eggs!
I have had a rooster for a month or so, none of my eggs are fertile
