When did chicken become a synonym of cowardice?

Question

Chicken is often used to mean someone is a coward. This is exemplified in the game of chicken.

When did chicken first become a synonym of cowardice?

Answer 1

According to this Quora answer on the exact same topic:

The primary uses, however, remain those that suggest weakness. Thus the early use to mean a girl or woman, which would become the more recent chick. Such chickens also suggest the 'cuteness' and 'fluffiness' of the creature.

The first example we have of chicken meaning a coward comes in 1600. It runs thus:

1600 W. Kemp Nine Days’ Wonder: It did him good to have ill words of a hoddy doddy! a hebber de hoy!, a chicken! a squib.