CoopsNPoops
Songster
I'm not sure where the air sacs are located, but its probably a ruptured air sac. Chickens don't have lungs like us, they have a series of different oxygen filtering methods. People often stick a needle in them to deflate them, but im not so sure that would be ok in a frail chick. Someone else may know more on that tho, or it may not even be a ruptured air sac. My wry neck chick (whom i had to cull) developed a big one under his beak/neck. I dont think his respiratory system was properly developed as he had trouble breathing from day 1.