I had 6 eggs I bought at the farmers market that were supposed to be fertile. One smelled bad at 7 days so I chucked it. The others I've left in the incubator. I candled them at 7 days, but only saw a dark shadow that moved as I turned the egg -the dark spot always ended up on the top of the egg when holding horizontal (but not the ends where air sac would be etc.) No veins or darker spot that could be an embryo. I just candled again at 10 days and I don't see any difference, dark shadow is still moving around as I turn the egg. No veins or darker spot inside the shadow. They are brown eggs, but not dark brown (Rhode Island Reds). I am going to keep going, but any thoughts? Could they be developing in there? Or are they infertile? The fact that the dark shadow is moving doesn't sound right? Also I don't see an actual embryo or veins...just this shadow.