So all of my eggs have pipped aside from the egg in question, 4 out of 6 have completely left the egg and are now in their starter tubs.
After four days of the first egg pipping, and three days after the first one came out of his egg, I made a small incision on the egg I was worried about considering it's siblings had been pipped for around four days.
There is definitely a BP in the egg, I can barely see him through the tiny slit; but he appears to be a full grown young one, the same size as the others.
The only problem is, I haven't seen any movement in this egg since I last candled at day 47. I even gently caressed the side of the egg hoping to see him twitch, tense up or anything but nothing happened.
I did the same thing to one of the eggs that had pipped, and he didn't seem to notice or move at all - but I am still super worried about this egg. It will just tear me up if this little guy made it full term only to die a few days before pipping to who-knows-what complication.