when mine go that long with no progress i help lil by chiping the shell away small pices at a time but if it starts to bleed put a worm cloth on it and stop for a few hours and start again i keep doing this til the chick is out when mine seem to have a had time
The membranes were dried and the chick couldn't do anything to get out.
If you can see in without opening - check the membrane if you can see it - doe sit look dry? whats your humidity?
My first move if the membrane is dry would be to up that humidity - I had a warm bowl of water handy and lots of paper-towels folded up into long pieces....
I took the egg out, onto a warm wet papertowel in my hand and picked off a couple of pieces of shell, try not to nick the membrane as thats when you'll get bleeding if you're too early - once you've picked off a few pieces - if you can ZIP the shell for the chick that might help as well. I put the egg back for an hour or so, with the paper towel still wrapped around it.
Make sure you UP that room temp as high as you can - I had a space heater next to me all the time - on HIGH (an oil heater if it makes a difference)
Every couple of hours I would remove the egg, and take off another few pieces of shell - you can SEE through the membrane and see if there is blood, if you see blood - wrap the egg and put it back for a few more hours.
Its a very long drawn out process. Each chick I helped out took me an entire day.