Hi guys! I was trying to candle some of my broody chicken's eggs and I could see through some of them but then some I could not see through one bit. The ones I could see.. I did not see any veins but I did see a dark spot that looked like a normal sized yolk. Another one was a very large looking dark spot that would slide around when I turned the egg. The other ones I could not get anylight through at all. I thought that maybe because they are the brown type, it is more difficult to see veins etc? Are the very dark ones that do not let light shine through fertile? Or just rotten? They have been sitting under her for about 20 days or so.