One of my silky girl has a large air pocket on her chest. It is not a ball like pocket, it is from the top of her chest to just under. It is not tight with the skin but certainly feels as though there is a bit of air under the skin. It feels spongy like a balloon that has lost some air. She acts fine, she has a brood of 10 chicks and is a great momma. Eats and drinks normal, but looks as if she is constantly walking around with her chest puffed out. I know that they have the four air sack, could one be leaking? Should I puncture with sterile needle to release the air? There are no vets that deal with chickens near my area.