Hen Feathering

[Ozchicken]

I saw some interesting birds at a recent club meeting. Apologies for poor photos.

These were hen feathered Old English Game. The male bird has feathering identical to a female. So no male sickles, hackles tail etc. It looks quite odd. These are quite rare here. I'm told that hen feathering is a dominant gene - Hf.

 

[Illia]

What I find fascinating is that he is colored like a hen.


Hen feathering isn't too rare in the US, some breeds naturally are henny-feathered, and then there's some games that are. I do believe it is dominant but I'm not completely sure.

 

[secuono]

Where are his wattles??

 

[Illia]

They're dubbed, just like his comb is partially dubbed.

 

[Ozchicken]

Yes, he's dubbed. I hope it's ok to post that kind of pic here. It's still legal to dub here, although it's going out of vogue and I think within a few years it won't be happening any more. Birds can be shown either dubbed or undubbed at the moment.

Here is a female from the same line. You can see her wheaten colouring. The Hf gene is not evident obviously.

Yes, the colouring is that of the hen as well. I have wheaten marans here and the males of that breed show the usual dark colours while the females look like this, so I know what you mean.

 

[Chris09]

Here is some information on the Henny Feathering Gene (Hf)


CHICKEN Summary :

The typical feathering of hens is part of their secondary sexual characteristics, produced by the action of estrogen. Much of this estrogen is produced from androgen in the ovaries by the enzyme aromatase. In certain strains of two breeds of chicken, namely the Sebright Bantam and the Golden Campine, roosters have the same feathering as hens, rather than the typical male form of feathering. This disorder is called henny feathering. It results from a mutation in the aromatase gene, causing thr gene to be expressed in the skin of both sexes. In males, this leads to abnormally high levels of estrogen, which in turn produces henny feathering. Henny feathering is interesting because it illustrates that not all mutations result in loss of activity; some mutations can cause a gene to be switched on in cells in which it is normally inactive.

Clinical Summary :

Apart from the hen-like feathers, males with this trait have a substantially reduced reproductive ability, probably because the increased levels of plasma estrogen inhibit spermatogenesis
(George et al., 1990)

Inheritance :

The aromatase gene is autosomal incomplete dominant gene, but the form of inheritance of henny feathering is not what is normally seen with an autosomal mutation, because the phenotype associated with the mutation
(henny feathering in males) can be seen only in males. This is an example of a sex-limited trait. Furthermore, the normal expression of the gene is seen only in females. Thus the two alleles at the one locus give rise to the two possible forms of sex-limited inheritance. The henny-feathering mutation also illustrates how two alleles can present more than one form of inheritance, depending on which trait is being considered. With respect to aromatase activity, gene action is co-dominant, i.e. heterozygotes have an enzyme activity mid-way between that of the two homozygotes. In this case, however, the activity in the skin of the normal homozygote is zero. With respect to feathering, the mutant is dominant, because heterozygotes produce sufficient enzyme in the skin, and hence sufficient oestrogen, to cause henny feathering.

Molecular Genetics :

This disorder is the first insertion mutation documented in any domesticated species of animal. In this case, it appears that the terminal repeat sequence of a retrovirus has been inserted into the 5' promoter region of the aromatase gene (Matsumine et al., 1991). This terminal repeat has a promoter of its own, which causes the aromatase gene to be switched on in atypical places, such as the skin of both sexes, giving rise to the henny- feathering trait in males. The actual peptide produced by the mutant allele is exactly the same as that produced by the normal allele, as we would expect for such a mutation.

Mapping Summary :

The Hf locus is located on the long arm of chromosome 1.

Information above from Ultimate Fowl

Chris

 

[Ozchicken]

Thanks Chris.

It's interesting that they call it a disorder. This is considered a legitimate variation on a breed here. I don't believe sebright breeders would consider it a disorder either. I guess it's a matter of perspective. I have heard that in the original use of the OEG it may even have been an advantage as another cock bird might mistake a hen feathered bird for a hen for a moment. I don't know if there's any truth in that though.

I have not heard that hen feathering results in reduced fertility. That's interesting. However, that wouldn't classify it as a 'disorder' unless a rosecomb is also a disorder.

 

[Lollipop]

Years ago I had Spanish Games. One hen would often throw hennie stags and regularly feathered stags in the same clutch. The quality of the birds was the same, but the hennies were highly sought after......Pop

 

[Chris09]

Quote:
Well lets look a the definition "Disorder" ,
Disorder: Disease, an abnormal condition affecting the body of an organism.
So technically it could be or could have been considered a disorder because it wasn't normal for a rooster to have hen type feathering do to high amounts of estrogen.

Between you and I,
I have no problem with Rose Comb and fertility.
I raise Rose Comb Rhode Island Reds and American Dominique and neither have a fertility problem.

Chris

 

[Ozchicken]

He must have been heterozygous for Hf if he threw half and half over a non Hf hen.