This is a good example of how basic composition works with lines and divisions of a photograph. You did a great job of applying the rule of thirds on several places in the photograph, turning the inconvenient fence into a centerpiece that determines the mood of the photo. The diagonal beams in the background do a great job as secondary line of focus, placing the kid in a world of lines.

Which brings me to the one thing that bothers me a bit about this photo, namely its journalistic element. I think it's save to assume that the boy is not actually locked up or in any way unfree. This may seem like a small nitpick, but I think the context of a photo is very important in this category. It seems to me that he is very interested in something on the other side of the fence (and about to start reaching for it, undoubtably another great moment to shoot ).

So my question is: what story do you want to tell with this photo? Did you want to share the fact with us that kids are locked up behind fences? Or did you maybe want to show us the desire for kids to explore their surrounding beyond the fences adults build? I'd say the latter causes a lot less friction with the reality in which the photo was taken.