How are you checking for fertility? The easiest way is to leave a couple of eggs on the counter for several days and then look at the yolk when you crack each into a bowl. If the egg is fertile you will see a little bullseye about 1/8 inch in diameter on the yolk. Then start saving your eggs to hatch.
No bullseye...your roosters aren't hitting the mark.
No bullseye...your roosters aren't hitting the mark.