Originally Posted by adrian
Detached air cells will move all around the egg when you move them. If they are doing this, in my opinion there are a few things to do to improve your odds of hatching the eggs successfully.
One, move them to an upright position, if they are not already in it. Egg cartons work wonders. In my opinion you want them very upright, not just slanted with the big end farther up, such as people often set them in Brinseas.
Two, stop turning them-- for the most part. You've turned them adequately for the first 11 days and that is very positive. This is when the embryo needs turning most of all, to help the blood vessels grow throughout the egg and to prevent the small embryo and its yolk sac from becoming stuck to one side.
From what I have learned about turning, which is more important in some birds such as parrots, it is mostly about the allantoic membrane, and its growth throughout the egg. By the halfway point in incubation, the allantoic membrane, which we see during candling as the network of blood vessels, should cover the entire egg. Which means you should see veining throughout the egg now, or very nearly. This is why during the second half of incubation, turning is far less crucial. This is lucky for your case. If I were you I would probably give them one rotation a day, in an upright position, but being sure that their air cells are always in a "normal" position at the top of the egg. Just "spin" the eggs in their cartons (if you choose cartons) once per day.
Three, I like to turn the humidity down quite a lot, if it is not already low. The air cell when detached will probably not grow. Thus, the last thing you want is to have chicks hatching in wet eggs, and if the air cells can grow, you want to encourage it as much as possible. I'm thinking quite low, like 30% or so, if not lower. Some people incubate at these percents normally. I would also highly suggest that when you go into lockdown, you refrain from raising the humidity much (if at all) until you see external pips. Then raise it to around normal for hatching; 60-65%. Your goal is to have the chicks pierce through the membrane and breathe, with what air space they have. That is most important of all.
I find that high humidity will soften the membrane, sometimes making it a bit gooey, and making the entire egg wetter. For a chick that may already have difficulty finding a dry space in which to breathe, the last thing you want is the membrane to be gooey and for there to be any liquid in its way. Usually, in most species, I do not bump humidity at all until I know they have internally pipped, but if you are very worried, 40-50% is probably a decent compromise. However, the membrane usually does not dry until it is hit by the outside air, as the inside of the egg is naturally moist. Fans will especially dry out the membrane. That is why it is probably best that you bump humidity as soon as you see the first external pip. Some eggs may be behind, but again, there are lots of compromises to be made.
You also must make some decisions. In the end, it is generally preferable that the membrane dries and the chicks must be assisted out of their eggs than the chicks drowning in their eggs before they can pip. It is a compromise I have taken before. Sometimes, or in some cases, you may need to assist, but it is possible that if you are careful, things will be all right. For example, I had an egg with a detached air cell last year, a silkie chick, and from the start of incubation I incubated it in an egg carton and only rotated it a few times. I found the less I turned it, the more stable the air cell became. So by half point I stopped turning almost entirely. Around 5-6 days before hatching I did stop entirely. I went into lockdown as I usually do, with modest humidity, and lo and behold, that egg was the very first to pop out. Fast, and energetic, and without a single issue.
It can be successful! I just highly recommend making sure you don't get the eggs too wet, and keep them upright and as still as possible from now on.
That is just my experience. Take it with a grain of salt always, because as they say, YMMV.