Soft bulge on hens chest

[ladykalous]

I have a 16 week old chick, she has always been the smallest. I found a lump on her chest today and its very squishy, about the size of a tennis ball. She eats fine, she is spoiled rotten and loves to be on my shoulder. Her overall behavior seems fine, just this lump! Should I be worried? The others aren't like this! Ironically, her name is Nugget.

 

[Tookie]

To me it sounds like its probably her crop.
Could you get a picture?

 

[A Justice]

I had the same freak out moment when my chickens started to fully develop. It's probably just the crop, a part of the stomach system used for pre-digestion.