I have lost most head between legs chicks, bur I did save 1. He was shipped and had a bigger air cell. I don't know if this is advisable, but I will tell you what happened with him.
I was worried about that one from the start. The air cell was too big, and when he fell behind in pipping like always I started with a small air hole and later in the day made it larger and moistened the membrane. That night, really late there was nothing happening . I saw no signs of life. I used a cue tip to try and get any sort of response and nadda. I believed he was dead. I slowly started to Peel of the shell, just the shell to figure out what happened. I got 2/3 of the shell off with no response to what I was doing when I pulled a bit of shell and a drop of blood formed. !!!!!!!!! DEAD THINGS DON'T BLEED!!! I stopped the minor bleeding and then it moved. I covered the whole egg in ointment and put it in a very small Tupperware container with a wet paper Rowland. I was SURE I doomed it. I was certain he wouldn't be alive by morning yet he was. I think pulling the shell off got some air to him. He got stronger and by evening he was able to be let out. He grew strong and healthy. That was a miracle. I don't know if that story will help, but never call it quits til after the fat lady sings ... twice.