I had thought that my hen was a black giant or maybe an black australorps, but some think she is a black sex-link... What defines the difference between them?
I would say she's either an Australorp or Jersey giant like you were saying, but I don't know what the difference is. Black sex-links have gold on their hackles and breast though.
Her feet look blackish to me... with white toes, so I guess that would be Australorps? Is that right? She just doesn't look as filled out as the pics on MM.