The oldest papers about this topic are:

Kimball, E. (1951). Pyle-Black Plumage in the Fowl. The American Naturalist 1951 85:823, 265-266
I have to scan it, when I am back to University in January.

Punnett, R.C. (1957). Genetic studies in poultry XIII. Recessive black. Journal of Genetics, December 1957, Volume 55, Issue 3, pp 562569.

Kimball, E. (1959). Recessive Black. Poultry Science,1959, 38 (1): 225-226

@ Zenith311 You have to ask the moderator Henk for permission by PM to get access to our documents area.

Smyth (1994) listed a Birchen allele as ERB, the RB standing for "red-brown downed birchen".
I think that this is, what Kimball called Pyle Black

Edited by Redcap (12/19/16 08:27 AM)
Edit Reason: Added Henk's Profile