I have an 8 month old chicken that I have thought all along was a female but now am questioning that. Because of her look and knowing the chickens that were on the farm where we got her, we are thinking she is part Buff Orphington, and part Jersey Giant. We bought her as a hen and added her to our flock with 2 other new ones. She was the only one to get picked on continuously by both my rooster and the other hens. Eventually the "bullying" got better. Now a few months later we are noticing that she is starting to pick on the other hens in the coop and I caught her yesterday, looking like she was trying to mount one of my females. We are not sure if this is a dominance thing or if we have a rooster here. She is huge in comparison to the other hens, but we chalked that up to possible jersey giant. We have also never seen/ heard her crow.
Any thoughts?

Any thoughts?