Sex-dimorph colored Thuringian Selfs: The cock coloring of the grizzles in the AOC class?

A sexual dimorphism with differently colored cocks and hens was proved in the 1930s and 1940s by W.F. Hollander for the gene Faded. The discovery led to the Texan breed. Due to sex, cocks have the hereditary factor 'Faded' twice, hens only single. This causes the much stronger lightening of cocks.


Fig. 1: Auto-Sex colored Texans, on the left a homozygous faded cock and on the right the corresponding hen color for a blue hemizygous faded hen


An allele of Faded, a gene with a similar effect at the same gene-locus, appears to have existed in the Thuringian Forest a century earlier. This can be taken from a report in the 'Gartenlaube' by Ludwig Storch in 1856. In his report on the country and people, he names the colors most valued in Ruhla in the Thuringian Forest. These include colors with similar names to those found in today's Thuringian Selfs. Inheritance occurs in the main color varieties according to the same pattern like at Texans (Andreas Leiß). The color effect of the hereditary factor called 'Frosty' is only weaker. Cocks of the Thuringian based on blue bar individuals are similarly lightened in homozygous Frosty like hemizygous females of the Texans. Females that only have the frosty factor due to their sex single are not or only slightly changed in coloration. In the case of the cocks, homozygous cocks are called blue ground colored, the females blue. They also exist, not listed in the standard, on the basis of blue-check pattern. In the case of the cocks, the checks stand out slightly in the shield. Breeders call them grey-ground colored, the hemizygous females remain blue checkered.



Fig. 2: Blue Ground Colored cock and Blue Bar hen (hemizygous with only single factor expression for Frosty).



Fig. 3: 1,0 Grey Ground Colored cock with a shell crest (Thomas Oschmann) and Blue Check hen (Walter Hunger)

In the dilution one calls cocks, with genetically bar pattern, Light Ground Colored ones. In the case of check pattern, they are Yellow Ground Colored, the patterns are visible in the shield. The diluted females are silver in bar pattern, and larked as a counterpart to the yellow ground-colored in the checkered ones. The yellow crescent on the chest indicates Lark Bronze appears to be involved. This can be seen in the non-diluted colors in the brown-red 'noster' there. The yellow color of the patterns on the diluted colored cocks is surprising.


Fig. 4: Light Ground Colored cock and silver hen from Frank Zetzsche (hemizygous with only single factor expression for Frosty).



Fig. 5: Yellow Ground Colored cock and Larked hen (hemizygous with only single factor expression for Frosty).

Thuringian Selfs did not receive a standard until 1951. In addition to the blue-, light- and yellow-ground color classes that only apply to cocks, silver bar, lark, blue bar, blue checkered and owls (grizzle) were initially recognized for both cocks and hens. During a revision of the standard, the peculiarity of gender-linkage, which was also noticed in Germany at the time with the Texans, was partly taken into account: the blue grounded, light- and yellow-grounded cocks were assigned the hen colors blue, blue check, silver and lark. All other colors, with the exception of the 'owl-like' (grizzles), were deleted. Why the exception of grizzles? They stayed in the Standard after objections from Thomas Oschmann. The objection was probably given in because of the proven long tradition of owls in the breed. This is expressed in the most popular colors of the time listed by Ludwig Storch 1856 (Fig. 5). Named are different kinds of grizzle like owllike, white-, black-, silver-, ground-owllike. Also, other terms are given in old writing, that fit to the today cock- and hen-colors of the breed.

Fig. 5: Most popular colors in Ruhla in the Thuringian Forest at Ludwig Storch (Gartenlaube 1856)

Grizzle remained in the standard in the 2004 ring binder, but with identical descriptions for cocks and hens. No lightened cock colour, as was to be expected with homozygous frosty cocks and the experiences in the other color classes! Thomas Oschmann must have recognized the error back then and at least guessed at the connections, as one could gather from an exchange of letters years ago. Because he reported on storks being bred, which he was not the only one to receive. At that time, most breeders could not imagine that these storked-like cocks are actually the cock color as counterpart of the grizzle hens. And this surprises in the strength of the brightening still now.



Fig. 6: White stork cock and grizzle hen from Frank Zetzsche (gender related the hen hemizygous frosty with only a single factor expression for Frosty).

This was proven in the re-breeding of the clean-legged Thuringian grizzles by Frank Zetzsche, who reported on it in the 2019 German Poultry Newspaper. From the stud book and when tracing the pedigrees, it can be seen that homozygous Frosty cocks with the grizzle factor are lightened to light storks. The special feature, in combination with homozygous Frosty, even when heterozygous grizzle (Fig. 6). Unbelievers can quickly reproduce this in their own breeding attempts. This means that grizzle cocks in the hen color specified in the standard are not homozygous Frosty. In breeding, therefore, other than the recognized color varieties will fall out of them. The auto-sexing nature as a breed is gone. The white storks, on the other hand, are the opposite of the hemizygous grizzle hens. Paradoxical when you have to show the color of the cock to a recognized color of the hen in the AOC class. But maybe you'll see them there!

It will have to be found out in practice how to breed most successfully for the best coloring of the grizzles in the color of the cocks and hens for the exhibition. From other breeds it is reported that permanent mating of grizzles with each other leads to lightening. This can be counteracted by mating hens with blue ground colored and cocks with blue hens from blue ground colored families. If such pairings result in blue cocks, or grizzle cocks in the hen color, then the mother comes from an outcross upon other breeds and does not carry the Frosty gene.


Hollander, W.F., Auto-Sexing in the Domestic Pigeon. Journal of Heredity, 33, 1942, pp. 135-140

Sell, Axel, Genetik der Taubenfärbungen, Achim 2015, S. 144-152

Storch, Ludwig (anonym), Land und Leute Nr. 5 Die Ruhl und die Rühler, Die Gartenlaube 1856, no. 27-29 in continuation

Zetzsche, Frank, Erzüchtung der glattfüßigen und glattköpfigen Schimmel bei Thüringer Einfarbigen, GeflügelZeitung 18/2019, S. 18f. (Creating clean-legged and plain-headed grizzles in Thuringian Selfs)