My husband found someone who wanted to give away 13 baby chicks, about 3 wks old- 4 Black Jersey Giants and 9 Barred Rocks. We picked them up today and foolishly just added them in with our own 4-5 wk chicks.. it's a beautiful day out so we brought them outside to graze on the grass (under a cage top) and noticed that one of them has a HUGE lump/bulge starting on its neck down to it's chest, right side. Then I noticed that ALL THIRTEEN have this! Is it a disease? Is it the chicken's crop? We have Barred Rocks that we purchased, who are about the same age & do NOT have this bulge. These chicks are kinda stinky & seem to be a bit neglected. My husband said they were in a box that was too small & it was all wet in the bottom. Could it just be their crop & they've kind overindulged on the food/water? When we put them into our brooder box, they went a bit crazy for the food.. HELP!