It is a separate competition from exhibition, although it is related. Showmanship is divided into age groups, with expectations increasing with the group age range. The ones I have observed are very much a learning experience, not a final exam.
Showmanship is educational, but is not necessary to participate in order to show. When I was in 4-H (15ish yrs back) I never did poultry showmanship, wish I did though. My concentration was with rabbit showmanship.
Showmanship is a class at shows, usually 4-H, where the handler is judged instead of the chicken (or other animal).
There is a proper way to show any animal and participating in at least showmanship training sessions will teach you how to properly handle the animal during a class at the show.