Because there was a rift in the time-space continuum, the chicken was stuck in an endless loop, repeatedly getting halfway across the road only to be mashed into paste by a mack truck. The chicken started having deja vu experiences before it finally figured out that it shouldn’t cross the road until an additional 15 seconds had passed. Once it did that, the loop was resolved, and the chicken was able to complete its objective of delivering supplies to Deep Chicken Coop Nine.
–Because a nearby ion storm made it impossible to get a transporter lock on the other side.
–Chickens undergo a biological cycle that compels them to cross the road once every seven years. They just don’t like to talk about it.
–It was seduced by the Dark Meat of the Force.
–The Answer and the Question are mutually exclusive. There is a theory which states that if ever anybody discovers exactly why the chicken crossed the road, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.
Kirk: To boldly go where no chicken has gone before.
H.P. Lovecraft:
To escape the horror on this side of the road, the most blasphemous eldritch abomination of elder night ever to seep forth upon an unsuspecting world from the interstitial blackness of non-Euclidean space and stalk cloven-hooved across the bleak and tenebrous wastelands of eleven overwritten pages.
Check out: http://www.chickenjoke.com/
Oh, and why did the Florida chicken cross the road?
To show the possum it could be done!
(If you live in Texas, substitute “armadillo” for “possum.”)
The Foundation Trilogy: Although we can predict with great confidence the behavior of large populations of chickens over generations of time, we can of course say nothing about the behavior of a single chicken.
Adelei Niska: “So now we are done with preliminaries, with little questions: Why you hold back eggs from me, why you cross road. Now we get to the real questions–About your true self… Now we get to meet the real you. Tell me-- [begins plucking feathers from the chicken] --are you familiar with the works of Shan Yu?”
Because the needs of the many chickens outweigh the needs of the one?
10-15 years ago, there was a SF anthology in England called Forbidden Planet (Named, I believe, for the comics shop in London; most of the writers and illustrators were Brit Pack comics pros). One of the stories was about a group of chickens stranded on a very busy highway’s median, subsisting on rain puddles, bugs and litter. The stupid ones drifted into traffic and were flattened immediately; the remaining ones evolved at an accelerated pace, developing rockets and teleportation devices to attempt to cross the highway successfully.