I was going to say the same thing. I cut on day 52 but cutting them a little earlier will not hurt. Maybe just cut the ones changing colors. It looks like your vermiculite was way to wet. The last couple of weeks the eggs start sweating alot and this is probably where most of your moisture came from. The color change could just be from condensation dripping of the lid of the egg box onto the eggs. Cut them open, I hope they are ok.
Matt