Roberta's poem doesn't exactly have an exact poetic form, since she's in a state of anger, which is why she's shouting her thoughts.
BIRDCAGE
How long for have I been such a display?
Only a symbol of sex to portray?
My freedom is locked in this cage from hell!
Nothing more than trapped in an iron shell!
Why do the peacocks form now around me?
Their dance has pained me for eternity!
Such frivolous filth only brings such pain!
Let all the feathered swine now burn away!
The fury I hold knows not such a bound
Their display sickens as they move around!
Only one as I to endure their dance!
A simple escape is my only chance!
My future has flown away from my hand!
Yet I only want life of my own Brand!
Forever alone in this hanging shell!
For simple want of friends I sing in Hell!
My toxic elixir sends grief to end!
The devil's juice is my only dear friend!
Humanity's friend so faithful to all!
I can never leave him. Never at all!