Scene 3, Steven tells a joke in which a rooster in on the point of raping a hen, but is distracted by some food
Stevens joke only comes a couple of pages before Stanley refers to both women as 'hens'
description of Stanley in scene 1, 'Since earlies manhood the centre of his life has been pleasure with women [...] with the power and prideof a richly feathered male birds among hens'
Stanley is then the rooster in Steve's joke, meaning he is a potential rapist.Blanche is compared to birds throughout the play then places her as his hen, not Stella
When Blanche is compare to a hen, its not simply highlighting her bird-like characteristics, but warns us of her sexual vulnerability to Stanley anticipating scene 10