3 of my 6 chicks (4-5 weeks old) have good size bubbles under their right breast - pic included

[xanaxnation]

The Brahma has it the worst. The bubble doesn't feel fluid-filled but it is soft and pliable. This is my 3rd time raising chickens from day olds, the difference this time is that i purchased them from a feed store instead of ordering them directly from the hatchery. the mass is about 2 inches across. any suggestions?

 

[Eggcessive]

I think this is an unabsorbed air sac, and should resolve on it's own. In humans this is called subcutaneous emphysema. The body will re-absorb this air. Some people have posted removing this with a needle, but I would not recommend this.

 

[MrsBachbach]

My first thought is a swollen crop. The chick may have an impaction somewhere that is causing food just to build up in the crop since it has no where to go. Food can sit in there and ferment causing gas and swelling. Remove it's feeder at night and check to see if there is any reduction in size the next morning. If it has gone down some, then some food is at least moving though it. Ideally, it should be emptied. Another way to tell is isolate the chick and see if it is still passing droppings.
Sadly, impactions usually mean a slow death. Did your chicks have access to any chick grit? They should be given a little every now and then.