This is the thread I was thinking of. Thanks for posting it.The best thing you can do to help is not rush the chick. I also had one do this too. In my case the chick had pipped internally into the air sac. After waiting an extra 12 hours I "helped" the chick by creating a very small hole in the shell at the air sac just to allow the chick to get oxygen. By the next morning the chick had finished the hatch on it's own. I could see along the way that the chick was moving and if I picked the egg up and tapped it he would peep at me.
Here's a link to the post about assisted hatching: