There were no veins it was all transparent or yellow so I highly believe the poor thing was starting to dry out.
Oh yeah, he was ready to come out! YAY!!!There was even pooh at the bottom of the shell once it was able to push itself out of the shell.
I'm sooo glad he's okay! He'll likely roll and flop around a lot before he gets his feet working right.
BE SURE THE FLOOR of the incubator is NOT SLIPPERY. Cover it with paper towels or a thin kitchen towel, something so he can get some grip. Slippery floor makes chicks with spraddle legs. You do NOT want that.