It has looked quite painful for quite a while now and today i saw this weird looking white thing hanging out of it (piece of egg?). Has anyone seen anything like this before?
My only 2 other guesses would be parasites or infection.
It also may help to put in quarantine. It looks like she has been pecked on. Quarantine doesn't have to be fancy. I use a large dog crate (sized for a border collie). If not in quarantine, the other birds may cannibalize her.
She looks infected. Bath her in a warm epsom salt water. The poop burns them. Read up on vent gleet, however, not sure if this might be part of the problem. Repost picture after you clean her up.