There are several things that need to be remembered about hatching eggs. First, 12 hours is nothing after a pip to be concerned about. I have had chicks go almost 2 days after pipping before making their way out. Second, the chick is wrapped up very tightly inside, head under wing, feet lying along side of head. Third, the correct humidity level during incubation is 50%, 45%, 40%, 35% 25%. What I am trying to say is that you really are better off monitoring the air cell than sticking rigidly to a specific hygrometer reading. 50% may be ok for a while, but maybe 40% is what is needed now, etc... If the humidity is too high chicks can grow too large and have difficulty hatching. Intervening MAY be required in just a few rare cases but normally it does far more harm than good.
Another very important fact to remember is that a chick NEEDS to run low on oxygen to hatch properly. If you look carefully at a newly hatched chick you will notice the back of their neck is swollen. This is a "hatching muscle" to put it simply, and is a very important part of the process. Within a few hours after hatching the muscle atrophies away. This muscle reacts to a build-up of carbon dioxide by spasming. When this muscle has a spasm, it jerks the head causing the beak to thrust outward and create another pip. The chick then starts pushing with it's feet to turn itself around in the egg, the spasms continue, and the egg "zips". Hatching is, largely, an involuntary process. If the original pip is enlarged, more oxygen enters the air space and can delay or prevent the hatching muscle from working properly. The chick then can need more help because the process is not working properly now.
I know it can be very difficult to leave things be, especially when we really feel that there is a need to help. However, in most cases, the chicks are actually fine and will be better off being left to their own efforts.
Richard
Another very important fact to remember is that a chick NEEDS to run low on oxygen to hatch properly. If you look carefully at a newly hatched chick you will notice the back of their neck is swollen. This is a "hatching muscle" to put it simply, and is a very important part of the process. Within a few hours after hatching the muscle atrophies away. This muscle reacts to a build-up of carbon dioxide by spasming. When this muscle has a spasm, it jerks the head causing the beak to thrust outward and create another pip. The chick then starts pushing with it's feet to turn itself around in the egg, the spasms continue, and the egg "zips". Hatching is, largely, an involuntary process. If the original pip is enlarged, more oxygen enters the air space and can delay or prevent the hatching muscle from working properly. The chick then can need more help because the process is not working properly now.
I know it can be very difficult to leave things be, especially when we really feel that there is a need to help. However, in most cases, the chicks are actually fine and will be better off being left to their own efforts.
Richard
