Spots in Hard Boiled Eggs

I just hard boiled some eggs and once the shell was off, I could see a dark spot in on the yolk. I cut them in half and took the yolk out for deviled eggs and the dark (sorta green) spot seems to be the fertilized spot that's on the yolk. The eggs have been sitting out for maybe close to a week (not refrigerated) but they've not been in temp's above 70. Is this normal in fertilized eggs? I mean, they've not in any way developed have they?