I'm going to guess he's a heinz57. A mix of mixes. I agree with Tink that brahma is unlikely, especially in the firs generation or two back. Pea combs are dominant, so neither of his parents had two copies of the pea comb gene. Brahmas also have a prominant "beetle brow" which your guy doesn't have.
Popular breeds vary from region to region, so it's hard to say what breeds are most likely to be in your boy's mix. Orpingtons seem to be perennially popular, so that's not a bad guess. The past few years marans have been pretty popular, and that could account for the feathered legs. Brahma could be in there a few generations back, feathered legs being dominant they could be passed on for generations. Rhode Island Red are also perennially popular and could have contributed to his color (RIR are black tailed red, could be where the black tail comes from)