what the heck is this

This hen is about a year and a half old and was acting completely normally until I just went out to lock my chickens up for the night… I thought she was dead because she was laying down and had her neck and head twisted on upside down. However, a quick search of crook neck said that it’s...

I'm in a byc local group and this has been a debate all day with over 100 comments. I figured I'd bring it to the experts lol. These are not my pictures. Is this some sort of worm or leaked egg whites from a hole in the egg?