on the side of his neck... last wk another roo and he went at it..both drew a bit of blood...nothing major we thought... today my son noticed he has a swollen area on the side of his neck by his waddle... I touched the area and it has a hard knot inside it... I took peroxide and it all fuzzed up... what do we do? let it go its course? if we need antibiotics what do we give?? we've never had a sick chicken before..heck this is our first round of chickens..help!