Junior display manikins, in the 12-14 year old range, are very rare, especially boys. But don't let them being hard to find keep you from buying some great clothing displays. Your junior clothing sales will increase with junior mannequins to show them, so take the time to hunt some down. Let your teen and pre-teen mannequins add life to your clothing lines, just as you would your adult clothing lines.
Junior mannequins may be harder to find, but don't let that deter you from creating a visual display that will pay for itself quickly in increased sales. Take the time to surf the web and find what you need, and if you don't find it, ask for junior mannequins!