The tuft gene is a dominant autosomal gene and is lethal when pure; it will kill the embryo during it's development. The tuft gene is represented by the symbol (Et) and a clean head bird by the Symbol (et⁺). According to researches the Homozygotes die at around 17-19 days of incubation, although a few may hatch. Most of these die within a week, but occasionally an "escaper" will live to maturity. One such Et/Et Araucana  was verified, but such a bird will not transmit his viability to future progeny. Heterozygotes also experience increased embryonic mortality at about 20 or 21 days of incubation.

        The tufts are a hard characteristic to achieve for showing. Due to the fact that they can grow in many different ways , sizes and shapes. Tufts can grow on both side of the head or only one side. They can be very big or very small or they can be even or uneven.  Therefore when a breeder hatch a few chicks a year with nice even tuft he consider himself happy.

Table of hatchability:

Table 1:

(Et,et⁺) X (et⁺,et⁺) = (Et,et⁺) , (Et,et⁺) , (et⁺,et⁺) , (et⁺,et⁺)

50% Heterozigous Tufted = 20% of these dead. Of the rest a portion will not show external tufting

50% normal = all live and vigorous

Table 2:

(Et,et⁺) X (Et,et⁺) = (Et,Et) , (Et,et⁺) , (Et,et⁺) , (et⁺,et⁺)

25% Homozigous Tufted = Dead

50% Heterozigous Tufted = 20% of these dead. Of the rest a portion will not show external tufting

25% normal = all live and vigorous