Why?

Why did the chicken cross the road? Who gives a damn? I hope one day that the chicken will be allowed to cross the road without having his motives questioned ...

This question has been puzzling me for quite a while. Why is the chicken the butt of our jokes? And I don't understand why half of our jokes start with "Why did the chicken cross the road?" These jokes aren't even funny. I've never found them funny, and I doubt I ever will. But, for some reason, we still tell them. Why? I just wanted to unleash that one on your asses. Answers, please :)