I had a very good experience with an egg with a detached air cell. It was a silkie chick. The air cell was totally detached -- they were shipped. I placed the egg in an egg carton, air cell up, and rotated it throughout incubation. However, I stopped turning a day or two sooner than I did with the other eggs, and turned less extremely. I would candle the egg every time I turned it (while still in the carton) to ensure the air cell hadn't moved a lot with the rotation. The chick hatched out extremely well, was the first baby to hatch. Total success.
It is very possible using the above methods and making sure your humidity isn't too high -- then the egg won't be so wet that the chick drowns immediately if it pips a little below the air cell, which is possible and may have happened with my chick. I found that the air cell barely grew (if at all) during the incubation process due to being detached, so it's something to keep in mind. If need be, you could probably wait for signs of internal pipping and then, carefully, make a hole at the air cell's end of the egg and make sure the chick can breathe once it pushes through the membrane. I've done that before with chicks that had various issues with success.
