Unable to See Through One Egg's Shell At All

[Pigeony]

So I've incubating eggs for a while now, both from other people's flocks and my own. I've never encountered this before. I have an egg in the incubator that is completely unable to be seen through. When I try to candle it, the entire egg is pitch black, you can't even see the air cell. It's been this way since I first candled on day 3. It's not even that dark of an egg, it's a small, light green egg. The hen is a relatively new layer. Other eggs from this hen are sort of difficult to see through compared to lighter tan and white eggs laid by other hens, but they are nowhere near as impossible as this egg. It just seems odd. I've left it in the incubator, the batch is set to hatch in a little under a week, but has anyone experienced something like this? Is this egg rotten? It doesn't smell and it was placed in the incubator day after it was laid. I can't really take a picture, because as I've said, you see nothing but black when candling.

 

[GirlsHuntToo]

The shell on the egg must be thicker than others, and colored eggs (specifically green and dark brown) are highly pigmented even though they may not look like they do. That would cause you to be unable to see threw the egg. There's likely nothing at all wrong with the egg or the possible chick inside.