Hi all, I just hatched this chick, 3 days late with very slight assistance, it was halfway zipped and struggling, so it went into some paper towel and clean polar fleece, into my heated blanket to help chip away the rest of the shell and soften the membrane. Very clearly overdue, fully absorbed yolk and membrane veins, pooping already and yelling its head off. What is this little extra bit at its tail? It's like a skin tag? No bone involved, no sign of infection, chick otherwise very healthy!