Anyone ever seen this

[Southern Bee Lady]

I have a chick about 3 weeks old. Just moved them out of the brooder into an area where I can sit and watch them better.
This chick has a strange buldge under its leg. It looks like an air bubble the size of my thumb. When the chick breaths in, the air bubble fill
up and then goes flat when the chick breaths out. I know I will probably have to put the chick down but was just wondering if anyone has seen anything like this before. Thanks for any help or comments.

 

[speckledhen]

Possibly a ruptured air sac, but I've never had that happen exactly that way. I have had a chick with that type bubble at the shoulder area, at the base of the neck. I let out the air with a sterilized needle on mine. There isn't much else you could do if it's just air under the skin.


Here is where the air sacs are located:

From this site: http://people.eku.edu/ritchisong/birdrespiration.html