She's a blue Cochin, I'd almost bet my life on it. Like a previous poster said, the "brown" color you're now seeing is sometimes called "brassyness" (sp?). Blue colored birds have a tendency to become brassy when they're exposed to a lot of sunlight, etc.
Def. a Blue Cochin though.
ETA: IF it's not brassyness, then it could be some sort of gold leakage due to the bird being a crossbreed. Did you get your girl from a hatchery, or feedstore?
That is my Anna in the photo on my web page. Her color though is definitely chocolate...as in the first posted photograph. I understand the term 'brassy" but that is not Anna.
She looks like chocolate milk and always has....
I just haven't seen one like her....