Limping, depressed, and a "bubble" under his wing?

[cuppycake]

My 6.5 week old BB white poult is not feeling well. I had him out to free range with his chicken buddies today and noticed that he is limping. On that same side there is a strange bubble under his skin beneath his wing, like right where the wing connects to his body. it's an air bubble, doesn't seem to have any fluid or tissue swelling in there. what the heck is it?

He didn't have any interest in exploring with the chickens, just laid down in the grass and stayed in the same place for most of the afternoon. He did get up once to go get a drink of water. As I gardened I threw worms at him as I found them and he ate a couple. Later I gave him some scrambled egg and birdseed mix as a treat because I felt bad for him. He would call out to me and the flock when he was left alone, but wouldn't get up to find us. When I put him back into the coop he went and had some food and water on his own.

I didn't see any obvious injuries to his foot or leg. Any ideas on what might be causing these symptoms and how I can help him?

 

[ivan3]

Could be anything from gas formation caused by infection triggered by contaminated vaccination equipment, to gangrene. However, it is often related to mechanical overpressure in an air sac and can be treated with varying degrees of success.

A couple of photos: http://www.thepoultrysite.com/publications/6/diseases-of-poultry/223/subcutaneous-emphysema

Good description of respiratory anatomy/physiology: http://www.worldpoultry.net/Breeders/General/2009/11/Rising-pressure-from-air-sacculitis-WP006961W/

Another shot (and good description of condition): http://www.pjbs.org/ijps/fin1339.pdf

Try drawing off air with a STERILE needle (clean area before/after draw with isopropyl alcohol/betadine). This might have to be repeated more than once. Probably be a good idea to add antibiotic to water, as well.