LEXX-
The dead do not allow chickens to cross roads.
-Kai, last of the Brunnen-G
Data: brief pause Ah. Humans consider it humorous to pose questions concerning the motives of domestic fowls which traverse thoroughfares.
HHGTTG: It just showed up there, since it was sitting on an infinite improbability egg.
Childhood’s End: To join the Overchicken.
<DR.SMITH>It obviously wanted to get to the other side, you Brainless Booby! Must I think of everything, you inane, mechanical Ninny?! OH! The Pain! The Pain!</DR.SMITH>
Lucifer’s Hammer: It was escaping the army of cannibal chickens.
The Wheel of Time: It didn’t really want to cross the road, but it was fated to so it whined a lot.
Red Dwarf: It only wanted to cross the road, but ended up quite a lot further because Rimmer was a smeghead.
A Song of Ice and Fire: Don’t underestimate that runty little chicken with the mismatched eyes. It may appear to simply be crossing the road, but nothing is as it seems.
Soldier: It’s going to kill them all, sir.
The chickens had become obsessed with the other side of the road. They had been there once as a group of naive chicks, but the unspeakable evil they encountered during that visit caused them to vow never to return. Sometimes, though, one of the group would feel it calling, perhapse something seen out of the corner of their eye, or a whispered phrase that never could be quite understood. They thought they had exorcised that experience, that terrible darkness from their lives, but then, the other side of the road would call. And in tremoring fear, they would answer. They knew they must cross the road, before it somehow crossed them.
Alien
On this side of the road, no one can hear you cluck.
Carousel is a lie! There is no renewal! Nobody’s ever been renewed, believe me!!
“My God, It’s full of chickens!”
To build a race of atomic superchickens to rule THE WORLD!
Thanks, Ed.
To get away from nerds.
La Jetee or 12 Monkeys: It was sent from a future time to ensure that the events leading up to the time of the great migration of chickens across the road did indeed occur. Yet although he was merely supposed to observe other chickens crossing the road, he became integrally involved in the events leading up to the great road crossing…
Minority Report: The chicken was a member of a quasi-fascistic police organization that used paranormals to predict when certain chickens were about to cross the road, and arrested & tried them for “future road crossings.” Until the day that a paranormal determined that he was destined to cross the road in a upcoming future moment…
– from Chicken-__It, by Stephen King! 
The X-Files - because the truth was out there.
Star Wars:
It was seduced by the lure of power promised by the Other Side of the Road.
Stars Wars, Episode One: To get the hell away from Jar-Jar!
Sword of Truth:
The chicken thought it had to cross the road to save Kahlan, but it got halfway across and almost got run over, and was forced to retreat, [insert 699 pages here] but then it turned out he didn’t have to cross the road after all, and everything turned out OK anyway, until the next time that is when nothing would happen again but everyone thought something would.
Uncanny X-Men:
the Chicken: Hear my fowl! No longer am I the chicken you once knew! I am fire! I am life incarnate! Now and forever…*I…AM…ON THE OTHER SIDE OF THE ROAD!"
Picard: There! ARE! FOUR! CHICKENS!
A song of Fire and Ice:
To die unexpectedly.