I've had a 4th one that pipped this morning, and there's a large hole, but now it's just chirping. It's not even trying to move. It's chirping right now, in fact, and it's been 12 hours. All it does is chirp and breathe, that's how I know it's alive. It should have no problem getting out, and I don't see why it doesn't. None of the others took this long, and the longest hatch at least showed some progress. This one looks much as it did this morning.
Humidity is good.
Just so that I know: When should one intervene and how?
ETA: Today is the 23rd day. Also, when should I give up on eggs hatching? I have 2 more in there, and one feels really solid. I'm not noticing any movement, but there wasn't noticeable movement with any of the other eggs before they hatched.