I am raising 10 CornishX from McMurray with 27 laying chicks I got from them at the same time. The chicks are a little over 3 weeks old and I noticed one of the meaties has some kind of sore near his vent. Any ideas what might have caused it and what should I put on it? Does he need to be separated from the rest of the bunch until he heals up? Any suggestions will be appreciated. This is my first attempt at raising meaties.