Brahmas are notoriously slow to mature. I am extremely confident that it's a rooster. Here is a picture of my Silver Pencilled Plymouth Rock hen to show what a female Dark Brahma's coloring would be. (Silver Pencilled and Dark are the same variety, just called Dark for Brahmas.)This bird is 4-5 months old. Are you sure it wouldn't be showing more signs it was a cockerel by now? I'm definitely not the expert here!
