Hi -- looking for some advice. I've read several posts about sour/impacted crop but I'm not completely sure that's what I have going on here. I have 5 chicks of different breeds all 5 weeks old. They are still in a very large bin set up as a brooder. (Coop to be ready next week) I have been using hay as bedding as I have so much left over from the horses. Last night, I noticed that the SLW chick had a lump about the size of a shooter marble slightly off centered on her breast. It was firm. I checked again this morning and it was still there but softer. Then I noticed another chick with the same soft swelling in the same place. Could they be eating the hay and it's causing these problems? They are all eating, drinking, and pooping just fine. Should I be worried? What should I do about it? Thank you in advance for any advice you can give me.