Carbon Dioxide causes the pip with muscle spasms

[Penturner]

Notice that even the article concludes the section on hatching with the statement that most failures are cause by Malposition (Chick is not in the correct position) or problems with Humidity. (both hi and low) It is interesting that the chick can actually completely fail to pip it appears if the head is even turned to the wrong side and the beak is not toward the air cell.
Co2 is a portion of the process but not something that replaces any of the other concerns that are commonly known. I have seen one article that mentions the Co2 level rising in the incubator during hatching as well. It is correct that to much Co2 will kill the chick, so will to much humidity and to high of a temperature.
Basically it is one more factor to consider as you evaluate the progress of the hatch.

 

[catdaddyfro]

Quote:
Thanks Penturner

I agree here on this post also, and as far as the CO2 levels in the egg from the chicks initial breathing of the air cell contents causes the initial spasms for pipping of the egg but if you had to have enough CO2 in the incubator air for the chicks to continue writheing with spasms to zip and break out of the egg and to also cause abdomen contractions to draw in the yolk sack, then the chicks that hatch out would surely die of asphyxiation.

My instructions on my incubator Little Giant 9200 desticntly says: Step 1, when you have 3 days remaining until hatch, stop turning eggs, or if an auto turner remove it from the incubator and place the eggs on the wire screen. Step 2, remove both red plugs from the top of the incubator to increase ventilation. Step 3, increase humidity. Step 4, do not open incubator except to remove chicks. Chicks can be removed from the incubator when they are completely dry. Some chicks may hatch late, so continue to run the incubator for a few extra days beyond the normal hatch period.

So that tells me right there that with both plugs open you would want oxygen in the incubator instead of carbon dioxide so the hatched chicks can breathe and not smother.

With that being said now it mostly goes back to wrong turning and wrong humidity levels being of the utmost importance. Surely if you've made it this far with the hatch then the temps. have got to be pretty close to right or you would have already had catastrophic results by this point of the hatch. I think the temps are a little on the forgiving side as long as they're kept in a normal range form 99.5* to 102.75* ish range, with the lower temps for forced air and the higher temps for still air incubation. The average temperature of a hen is 105* to 107* and I'm pretty sure there's not much CO2 under a broody hen as she's pretty much out there in the wide open with nothing to make CO2 but her breath.

Here's some info on troublshooting hatch chart out of Raising Poultry the Modern Way.

Dead Germs: Embryos dying from day 12-18, 1. Wrong turning. 2. Lack of ventilation.

Remedies: 1. Close temp. regulation. 2. Plenty of fresh air in incubator room and good ventilation of machines. 3. Feed yellow corn, milk, alfalfa meal, and fish oil.

Chicks fully formed, but dead without pipping: 1. Improper turning. 2. Heredity. 3. Wrong temperature.

Remedies: 1. Turn eggs 4 times daily. 2. Select for high hatchability. 3. Watch incubator temp.

Eggs pipped, chick dead in shell. 1. Low average humidty. 2. Low average temp. 3. Excessive high temp. for a short period.

Remedies: 1. Keep wet bulb temp. from 85* to 90* F. 2. Maintain proper temp. throughout hatch. 3. Guard against temp. surge.

Sticky chicks, shell sticking to chicks. 1. Eggs dried down too much. 2. Low humidity at hatch time.

Remedies: 1. Carry wet bulb temp. at 85* F. between hatches. 2. Increase wet bulb reading to 88* to 90* when eggs start pipping.

This is the info I go by and nowhere in the whole book is there anywhere a mention of needing the incubator to have cabon dioxide in it. Seems theres a lot about getting it out and having oxygen in there to me.

Happy hatching everybody,

catdaddy

 

[chickenmeadow]

Good points about the level of CO2 in the incubator. From what I had understood, it was the level within the egg, which caused the membrane pip & then the 1st shell pip (not including the zipping, which must be their instincts kicking in to "get out of a tight spot"). As mentioned by some in this thread, the CO2 is only a part of the factors which allsow for hatching. Good comments everyone, food for thought. It's all so facinating!

 

[Penturner]

The way I read it, the internal pip is the moment the embryo becomes a chick. this difference is marked by the first breath of air the chick takes. It then makes the external pip which gives it more oxygen, But I am not certain that is nearly enough even at that point. The chick is developing and now actually breathing inside the egg. Although from almost all description of an egg hatching I have noticed there is a marked pause after the external pip and the zip. something is having to kick in at that point. I think it woudl save a lot of chicks if it was discovered just what that something is.

 

[patandchickens]

Quote:
Actually AFAIK it *is* pretty well understood from a scientific standpoint... it involves the metabolic and anatomical switchover from doin' yer gas exchange through the blood vessels of the membrane to doin' yer gas exchange through the blood vessels of the air sacs (lungs). Some googling will get you references at least, but you may need online journal access or a university library to actually read the papers.

Frankly, since my understanding is that commercial hatcheries normally achieve a very high hatch rate, I think the fault is not so much with our understanding as with peoples' incubators and the management thereof

Pat, speaking as someone with *known* problems with incubator and management thereof <g>