hm, odd color changes. Hard to say then. I assume it developed the spots recently, when you created the thread, and didn’t have them when you began incubating? I have a terrible short term memory and I’m too lazy to go read through again. Haha. (Sidenote, I gave myself a heart attack one time when I used pen on a duck egg to mark the air cell. I had misted them and picked one up and got freaked out for a second until I realized I had made the ink run...

Haha. Don’t use pen. Lol)
my 3-day hatch took longer because I was impatient and opened a viewing hole in the air cell. He wasn’t ready (at all) so I put tape over it and put him back in. But messing with them can mess with them to the point of doing damage, even if you don’t do anything extreme, so it’s hard to know what the best option is for you with this one.
I think if I were to start picking at it, personally, I would be opening it up enough to see (doesn’t need to be a very big hole) and then I shine my light from the side and see what I can see. Alternatively, I would maybe pick a tiny bit of shell off over the bruised area, being extra careful not to puncture or nick the membrane underneath. That option is more risky.
I’m not sure what to recommend as the best course of action for you here. The conservative approach would be to leave it alone and sit on your hands, distract yourself with the others once they hatch. A little more daring would be to open up the air cell just enough to get a peek and see if it’s moving around in there. Daredevil level would be picking away some of that shell and seeing what the membrane looks like. Keeping in mind that the more you do, the higher the risk that you may cause damage inadvertently, no matter how careful you are. I killed a chick once that way when I first started because I was impatient and didn’t start carefully from the air cell.
