The lethal gene in araucana kills 100% of the homozygots and almost 20% of the heterozygote this dominant Autosomal gene causes some severe abnormalities in the embryonic development of the head, it couses an incomplete fusion between the hyoid and the mandibular bons, cause a dysfunctional skull and death.
Yeeess, now I remember - the abnormal skull development.... thank you for clearing that up.
..... How did this bird ever make it this far?!![]()
Only the Recessive homozote and some of hetero' survives, that is enough.
It is like the genetic of Huntington's disease
https://en.m.wikipedia.org/wiki/Huntington's_disease