hatched this guy nov 15, 2012. will be crossing him to some whites that made the tatanka standards to see if he passes it on, looks like the blueprint may be whwh Br+Br+ yw+yw+ e+e+ pi+pi+ hfdTt Robby from jmf found this on the subject, This is one of 9 articles I have about this mutation.... hfdTt...... Head skeletal abnormalities associated with the throat tuft mutation (hfdTt) in the Japanese quail. Poult. Sci. Aug 1990 M Tsudzuki, N Wakasugi Hereditary abnormalities of head skeleton ascribed to embryonic visceral arch defects were investigated in Japanese quail homozygous for the throat tuft mutation (hfdTt). Differential staining for bone and cartilage of 15-day embryos revealed partial deletion or irregularity in the mandible, basiparasphenoid, hyoid apparatus, and quadratojugal bones, incidences of which were 84, 44, 40, and 18%, respectively. Incidence of the head-skeleton abnormality was 88% when individuals having at least one of the abnormalities mentioned were regarded as abnormal. Throat tuft (hfdTt) and ear tuft (hfd) homozygotes showed distinct differences between them, although both alleles are associated with visceral arch defects.