I put 6 fertile eggs under my broody hen about 2 weeks ago. Since then, 3 of the eggs (when candled) have shown that "bacteria ring," so I got rid of them. The other 3 eggs don't show anything when candled at all. They're completely dark -- no ring, no veins, no spots. Any clue what this might mean? Should I keep them going for the next week, or order some more and try again? Thanks.