Abstract Ancestral wild stock of the Cornell Red Junglefowl flock, acquired by the writer through the courtesy of Dr. F. B. Hutt, were of Cochin-chinese origin (Hutt, personal communication). Two cocks heading the flock were distinctly different in phenotype despite many years of inbreeding. One approximated the Cochin-chinese subspecies phenotype, whereas the other resembled the Indian subspecies closely. Hybridization is usual at territorial boundaries of parent subspecies (Delacour, 1951). Among male progeny of the Cochin-chinese sire, there appeared a cockerel with considerable red flecking in the breast. Mated to three sibling females, the novel male produced 11 sons (5 black-breasted; 6 red-flecked breast). One of the latter red-flecked males was mated to P1 dams, yielding 9 sons (5 black-breasted; 4 red-flecked breast). With sibling females, the same male sired 14 sons (3 red-breasted; 9 red-flecked breast; 2 black-breasted). Experimentation is still in progress, but it appears a mutation occurred, affecting expression …