4h standard's used for judging can vary a lot from place to place....some counties and states engage judges that use APA standard's, others not so much. Most, especially for the jr. Classes are pretty lax. Showmanship classes are about the handler, not the anilmal....is this bird easy for your son to handle?
I would enlist the expertise of as currernt poultry project participant (check with the extension office if you don't know any) and have them mentor your son and assess the bird.... they'll be familiar with how things are for your locality