I have copied and pasted a message I received from another reader. These are the instructions I followed. The last egg zipped almost all the way around- about a 1/2 inch area of shell that he could not get to. I removed that portion with tweazers and he stretched out- however, the membrane was stuck to him both on the top of the shell and bottom. Using warm water and a cotton ball and a q-tip I softened the membrance enough to remove it with tweezers. I went slowly and was so gently because I could tell it would pull his skin. Finally removed all areas and placed him back in the bator. He is doing soooo well.
Here's the post: (remember all of this did not apply since our chick had already absorbed the yolk and was basically just stuck.)
Begin peeling the shell from around the pip site very carefully. Once you have about a quarter size hole go ahead and carefully peel the white membrane. This is the membrane in between the shell and the actual sac the chick is in. If you need to wet it to help that's ok. I find that sometimes it's just to thick for the chicks to get out. I am sure that humidity has something to do with it even if you have it up to 60+. Our home made bator's just are not as good as mom no matter how fancy. Ok once that's done you can see the sac. If you see a lot of veining keep wetting it with warm water so you can see what your doing. Now this is the important part. Oh and if you peel the membrane and nic the sac it will bleed, don't panic. Just put a damp warm papertowl around the egg and don't cover the babies head. This just means that it needs to cook a little longer and that's ok, just keep a close I on the chick. I have had them turn all the way around at this point and get stuck, and of course not watching they did not make it. Anyway,back to the important part. Just keep peeling the shell and the membrane away until you have a large part of the eggs peeled away, as much as you feel comfortable with. You see ware the chick has pushed it's beak through the sac, very carefully with both thumbs and a light touch pull back the sac to separate it, do not pull straight up or peel, just separate with your thumbs very gently. If there is a lot of sac fold it over the edge of the egg that's ok. Now, gently lift the chicks beak up so the chick's head is not tucked in anymore. Go slow with the next step if you accidentally make a wrong move and separate the chick from it's umbilical that's attached to the egg, the chick will bleed to death in seconds. Also by going slow you can see if the chicks yolk sac is absorbed. If you find that the belly button is a little under developed yet or the yolk is still not fully absorbed just keep everything moist and wait. You may be waiting for as long as 24 hours for things to correct them selves.Chances are if it's been 21 days your good to go. Sorry jumping around again. So what I do when the chicks head is out is turn the egg on it's side in my palm or soft cloth until the chick starts to move from the egg and then peel a little more if I need leaving just the last quarter of the egg intact. Put the chick back into the incubator, watch it, when dry and fluffy you can move to the warmth of the brooder. The fun part is when it open's it's little eyes and your the first thing it see's, Hi MOM. Sorry this is so long but it's important you take it slow. In time you will develop your own routine. I hope this helps. You do what you think is best for your chicks.