Oh no I did all that searching, look where you made me go.
https://mymodernmet.com/different-types-of-chickens-photobook-monti-tranchellini/?utm_source=newsletter&utm_medium=email&utm_campaign=portraits_of_most_beautiful_chickens_on_the_planet_capture_their_underrated_beauty&utm_term=2018-03-13
I would have guessed blue Wheaton if he'd had any kind of blue undertone to him. Perhaps he is and there are other dilution factors or white factor. Or he could be a buff with some kind of dilution. He does look like he's darkened as he's aged.