Most will tell you to leave it alone and it will reabsorb. That has not been my experience. The chick will give himself a hernia by stepping on the egg sac that will be difficult to stuff back in. This will look like a loop of intestine is hanging out as well as the egg sac which will blacken with time. The other chicks will instinctively peck at it and give the chick a slow miserable death if not isolated. If the chick has a hernia he will probably die, even if isolated in about 3 days. I would cut off the egg sac and cauterize the stump immediately or clamp it for 30 minutes especially since its already broken. The dangling mess he is dragging around is inviting infection and will almost certainly be stepped on pulling out things that won't go back in and making life impossible. I would also dip his bill in sugar water and keep him warm and isolated. Very tiny amounts of sugar water will keep him going.
Would it look like this?
I clipped because it was causing bleeding and pecking and her legs were getting tangled........... the V part was around her neck.