There is an age old question, that everybody knows. Its not "Why are we here?" or even "What is the meaning of life?", it is the simple question of: "What came first - the Chicken or the Egg?"
Now, the first thing that people think is that, well, of course the egg came first, because the chicken comes from the egg. But then the realisation slowly dawns that the egg had to get there first and therefore a chicken had to have laid the egg. But of course that chicken would have had to have come from an egg, because chickens don't commonly have a habit of simply popping into existence, so therefore there must have been an egg to hatch the chicken from... so where did that egg come from then?!
At this point, most right thinking people decide to think about something else.
But lets go a bit further here ...
Charles Darwin has this theory of evolution. He says that basically the success of an organism depends on its ability to adapt to its environment, and that the survival of that organism depends on how well it fits into the environment - survival of the fittest, if you will. So where does the chicken fit into all of this? Now if you want to go down this path, (make sure you're not eating any chicken at the moment) which is a bit sticky and involves quite a lot of sex then read on.
One day, probably millions of years ago, a creature that was a bit like a chicken, but probably not quite - maybe it had feathers and 'clucked' a bit but looked like an ostrich - mated with another creature that was a bit like a chicken but not quite - it probably pecked and was a bit shorter. This creature layed some eggs. But somewhere in the process of the creation of those eggs (very complex and biological, but has a lot to do with sex) the DNA of the creatures mixed and matched a bit. Subsequently, when the egg hatched, oooooh! there was something that looked very much like a chicken! Now if many of these creatures mated you get a new colony of chickens. There. So basically, if you follow this line, the egg came first, but it wasn't laid by a chicken.
Although this is probably a nicely accurate scientific answer, its a bit boring, isn't it?
Now the less scientific minded of you might prefer something like this - now its a bit odd, but open your mind and see where it takes you.
Firstly, you have to accept this premise - Chickens were a highly advanced and enlightened race, somewhat let down by the fact that these immense minds are kept in small, feathery bodies that taste rather good with gravy.
Secondly, you have to accept this premise - Chickens invented time-travel. Really.
Thirdly, they've forgotten all this.
It goes something like this. Thousands of years ago, while man was still trying to work out whether the ground looked inviting or not, the chickens were at their most advanced stage of evolution. They had asked themselves all the philosophical questions about life, the universe and everything, and had come up with an answer to the question "Why are we here?". The answer was this: "Because we put ourselves here". They worked this out because it seemed the only logical answer to the chicken and the egg question. They figured that as there had to have been a chicken to lay the egg that hatched the first chicken, they must, at some point in the future, invent time-travel, go back to a time when there were no chickens, and kick start their own race. From then onwards they pooled all their resources and scientific minds in the effort to invent a time machine. They succeeded.
Now this is were it gets a bit mind-bogglingly paradoxical.
Unfortunately, the eggs that they took back in time were from a pretty dud batch, coming from the P.E. teacher caste of chickens of the time. This is how the third premise came about. The chickens that hatched from those eggs obviously had to mate with each other so you ended up with a race of animals with many of the traits of the common or garden hillbilly, with the exception of running around with a shotgun, shooting at things. Subsequently, they never evolved beyond this point, therefore never reaching the peak of scientific achievement required to invent time travel, therefore, technically negating their whole existence. But time, being ever the comedian, didn't seem to mind this slight tear in its continuum and continued as if nothing had happened.
Hence that is why chickens are so dumb. It was their own fault.