Done some research on this:
Plato says it was for the greater good.
Karl Marx says it was to escape the bourgeois middle-class struggle.
Machiavelli says so that its subjects will view it with admiration, as a chicken which has the daring and courage to boldly cross the road, but also with fear, for whom among them has the strength to contend with such a paragon of avian virtue? In such a manner is the princely chicken's dominion maintained.
According to Albert Einstein, whether the chicken crossed the road or the road crossed the chicken depends upon your frame of reference.
Aristotle believed it was to actualize its potential.
Salvadore Dali says it was a fish.
And Gilligan says the traffic started getting rough; the chicken had to cross. If not for the plumage of its peerless tail, the chicken would be lost. The chicken would be lost!