We have 10 hens & 2 roos. Olivia is acting fine eating well but upon catching her & inspectiong her we found her red underside & bottom and this hole under her wing. She is under a year, not sure if she is laying, gets along well with the other girls. What is this & what do we need to do for her? Not sure is she should be removed. Checked for lice/mites whatever. Can not see anything/ no one else has any syptoms or feathers missing.