Can i help a baby chicken getting out his egg

Okay, what i am about to tell you breaks about all of  the chicken hatching rules, but this is what i do. When I have a broody hen, or if i'm hatching some chicks in an incubator, and if a few days gone by after there due date, and they are still moving/peeping i go in and help. Most of the time they will have pipped the shell to where you can see their beak but in your case, it seems like its not even piped! So what I do is puncture a whole into the air cell part of the egg with my nail. BE CAREFUL OF THE CHICK!!, then I basically begin to take the shell apart to make an opening around the chicks face. I wont completely do it, because the chicks manage to take it from there, but remember!!!! >>> the chicks should absorb the yolk. Make sure you are very careful when doing this! 

Good Luck!

Go in a dark room with a strong flashlight and the egg (hold the egg horizontal only).  Shine the flashlight THROUGH the large end of the egg.  See the lighter part?  That's the airsac.  It should be at or near the larger end of the egg.  Start chipping egg at that spot of the airsac.

One of our members here (Pete55), wrote some great material on hatching.  I have used his techniques with great success.  Here is one of his posts that has a fabulous section on "intervening".  I would act quickly before you lose that chick.

http://www.backyardchickens.com/t/491013/goose-incubation-hatching-guide-completed

The section on intervening is pretty far down in the article.

If you are only at day 21, why intervene?  I wait until day 23 or 24.  Have you done the float test yet?