How old are kids in question? Elementary school, middle school, high school?
Where are you located generally?
4-h is a great option. I’m in OH and my middle school kid shows chickens at the county fair through 4-H. When possible we’ve gone to see chickens at other fairs, like state or large county fairs when visiting relatives.
The Ohio National Poultry show (largest in the country) will be occurring next month in Columbus. kids can show chickens in shows like this in a junior category.
there are regional clubs that also offer shows and swaps and have junior categories. Such as the Dayton Fancy Feathers club in Ohio, but there are some other big ones in other locations.
You can get a membership to the American Poultry Association, they have a junior category.
There is a newspaper called “Poultry Press” that you can subscribe to. They feature articles in junior winners, shows, clubs around the country and have informative articles.