“Recessive White Chick Down Color: What Does it Mean?”
I have noticed several questions from Ameraucana breeders asking about variations in the chick down of their recessive white Ameraucana chicks.
Questions such as “Why do some of my white Ameraucana chicks have a smoky appearance?” or “Why do some of my white Ameraucana chicks have yellow chick down?” or “What chick down should I be selecting for in my white Ameraucana chicks?”
The C locus is multipleallelic. White Ameraucana carry the genotype cc. The Recessive white (c) gene can inhibit both eumelanine (brown/black pigment) and phaeomelanin (red/yellow pigment). Occasionally phaeomelanin may leak through. Interesting tidbit: Some research has shown that recessive white birds can exhibit yellowing in the hackle, saddle, and wing bows as they increase in age, suggesting that the inhibition of pheomelanin by the recessive white gene may be reduced in older birds.
Early research concluded that there was an association between the presence of Extended black (E) and smokiness in recessive white chick down (Jaap, 1942), but later research refuted this finding (Jerome and Cavers, 1952).
✅ Smokiness can occur in the presence or absence of E.
Jerome (1952) completed some studies on poultry that carried sex-linked silver and autosomal red while exploring recessive white chick down. He found that autosomal red could account for salmon tints in the down of recessive white chicks that were homozygous for silver. Additional research during this study led to the conclusion that recessive white chicks that are homozygous for gold could also create salmon tints in chick down.
✅ Salmon tints in the chick down of recessive white chicks may be due to autosomal red or the presence of homozygous sex-linked gold.
Extended black (E) helps to suppress pheomelanin (red pigment). Sex-linked silver (S) also helps to reduce the expression of pheomelanin as it inhibits the presence of gold and red pheomelanin in feathers.
✅ Being homozygous for E and S is an important genetic component of recessive white birds.
Interestingly, the expressivity of the silver and gold alleles can be highly influenced by the Columbian gene (Co) and Extended black (E). The addition of Co enhances the visual differentiation of gold and silver on chick down in all but Extended black (E) birds.
✅ The Co gene does not enhance silver or gold identification on recessive white chicks that are based on E.
Hopefully this post is helpful to someone out there!
