Stupid, cowardly and easily frightened, sexy, comedic

The stupid, cowardly and easily frightened chicken: Chickens have a tendency to run around in panic, because they cannot fly away from their enemies. This created their image as dumb and panicky creatures. In many languages the phrase "to run around/operate/work like a headless chicken" also expresses this image.
In the English language "to chicken out of something" means you're a coward. Calling somebody a "chicken" and making hen's sounds is seen as a huge insult.

The sexy chicken: In many languages the word "chick" is used to describe an attractive human female. A hen night is a bachelor party for women.
The comedic chicken: Just like ducks chickens have an amusing way of walking and are thus often portrayed as silly characters.
The cock/rooster who has delusions of grandeur or is vain: The "Chanticleer and the Fox" tale from The Canterbury Tales, Foghorn Leghorn, , Rocky and Fowler in Chicken Run,