Train of Thought, Interrupted

After watching and later discussing Girl, Interrupted I am very interested in the director's motives. We talked about how the story teller hides things from the viewer and leaves ends untied, if you will. Upon arriving at Claymore, Susanna meets her roommate Georgina. They talk about the other girls' and their conditions. They also discuss why they have been sent to Claymore. Georgina tells Susanna the story of Polly's burns. After all is said Georgina closes with the fact that she has been "sentenced" to Claymore because she is a pathological liar. As a viewer, I am unsure if Polly really burned herself or not. Also, what is the deal with the chickens? I keep asking this in class but don't feel like I'm getting a real answer. There's got to be something deeper than "The chickens connect to Daisy's father because he sells chickens". I plan on further researching this and getting back to you later.