The chicken in question is just about 3 months old, a silver-laced Wyandotte. She has always been the smallest of the bunch, but has seemed normal otherwise (she is 1-2 weeks younger than some of the other chickens). She has for a while not seemed to have much of a neck, which made her seem even smaller than her fellow pullets. I didn't chalk it up to anything though, and assumed that it had something to do with her being lowest in the hierarchy. A few days ago I noticed that she seemed a little, well, lopsided. At first it wasn't very noticeable, but yesterday it definitely was pronounced. It seems about the same today. It is hard to tell if she has her right side puffed out, or if it is her neck and head that are pulled to the left. There is a mass on the puffy side, but I am assuming that it is her crop. It doesn't feel particularly hard (a quick audit of the other pullets showed her to be about as squishy as the others). She has the appearance of having no neck, and I am not sure if she is pulling it close to her defensively or just lets it sit there naturally. Just in case it is an impacted or sour crop (didn't smell sour to me) I hung out with her for about an hour in my bathtub, and massaged her chest gently. She doesn't seem bothered by the mass, or by her strange way of holding her body. She seems perfectly happy to run with the other chickens, and has normal and frequent poop (bathtub test proved this). She doesn't seem particularly lethargic, and there are no wounds on her. Vent looks fine to me. She's been hopping around the bathtub and climbing all over me. Eating and drinking with gusto. I am just finishing with the chick feed, and about to transition them over to meat bird feed for the next month or so before getting them to adult laying feed (as per the instructions of my local farm supply people). The chickens have been in a large yard (30'x30'), and have been chewing on quite a few of the weeds in the area, in addition to their chick feed and plain water. Here is a picture of her, taken last night. I am a first time chicken owner, so I'm a bit lost.