infertile eggs happen, it's best to remove the egg and as much of the surrounding substrate w/o disturbing the other eggs. i've been told that good eggs actually have a protectant in them that prevents mold from growing on healthy eggs, i've also been told not to throw out an egg unless it discolored. I've actually had an egg sprout white fuzz 4 months in it never discolored, and hatched 2.5 months later!