I can't tell from the pics...is this area of concern separate from the cloaca/vent?
If it is not, you are dealing with a mild prolapse--clean up the tissue, apply prep H to shrink the tissue, then attempt to push the tissue back in using water-based lube (like K-Y) and a q-tip. If you're lucky, it will stay in. Needs to be done fairly quickly because the waste will start to back up into the bird. I had two chicks arrive with prolapses from shipping/cocci, was able to save one.
If you see a separate cloacal opening and this area is below it, I agree it could be the umbilicus...sometimes chicks with less than ideal incubator experiences can hatch without everything properly absorbed and the umbilical area can have a scab. Which can attract the attention of other chicks who peck at it. I'd clean it up (soap/water) and apply Blue kote as it is an antiseptic as well as an anti-pecking product.