No question, the other posters are right Black Australorp hen. I have 6 of them. Great layers and pretty funny personalties. My Head Rooster In Charge (when I am not in the coop) is the same. He is a FANTASTIC rooster, so if you get a chance at a roo I don't think you would be dissapointed either.
Thank you all! I'm so happy and relieved. If she was a rooster, I would have to get rid of her because we can't have roosters here in New York City. My students will be relieved also.