Recently my pr had been Laing egg, but the she became broody, butI took the egg out since there was no rooster. She laid a total of 13 eggs. My neighbor though has some hens and rooster but the will only go broody for a while and abandon the egg, they won't sit for the whole 20-21 day for the eggs to hatch. She gave me 13 eggs to put under her, but I don't know if they are fertile or not! What do I do?