This should help................ Understanding The Hatching Process
The initiation of hatch occurs partially from the increased carbon dioxide level in the egg. This process causes the embryo to begin twitching it's muscles allowing the inner shell membrane to be punctured by the egg tooth. The chick then begins breathing the air in the air cell. Using its egg tooth, it pecks at the shell thousands of times and after a few hours the chick pips a small hole through the shell and begins to breathe air directly from the outside. After the chick has made a hole in the shell, it stops pipping for 8+ hours sometimes up to 24 hours and rests.
During this time, it is acclimating its lungs.
After the resting stage is completed the second stage of pipping begins. The chick begins to turn slowly inside the egg. As the chick turns counter-clockwise it uses the cutting edge of the chick tooth to chip away. As the chick progresses in its movement around the shell, it begins pushing on the large air cell end of the egg. Squirming and struggling! YES STRUGGLING! The chick works feverishly pushing at the cap. Finally with a shove the chick breaks free from the shell wet and exhausted. When the chick is freed completely from the shell it lies still. Its energy has been virtually exhausted, and it is extremely tired. After resting the chick begins to gain more and more energy and coordination of its muscles.
BREATHE!
That’s right, take a deep breath, calm your nerves and RELAX!
There is no rush to get a chick out of the shell!
"The developing embryo has lived in this shell for well over 3 weeks.
It has survived off of the contents of the egg for that entire time. The only thing it has absorbed from the outside is Oxygen. As long as the chick is getting Oxygen, there is nothing urgent. Too many people feel the need to rush in and pull a chick out of a place that has served it well for 3-4 weeks. There should be no rush to get a chick out of the shell if it can breathe. As long as it has access to air through the pip, it can sit there all day, even after the blood vessels recede. It's not going to starve. It has plenty of yolk. It's not going to dehydrate, unless you get impatient and begin removing shell before it's time to do so causing bleeding or too much exposure to outside air."
http://www.avianresources.com/Nursery_Mgt.htm
