A Tough Call; Feathered Shanks

I realized early on that the first chicken had rather unusual feather appendages, but I would have missed this next one except for a translated excerpt from early writings by Professor Alexander Sergeevich Serebrovsky (1892-1948), a prominent Russian geneticist.

I knew about feathered shanks and toes in modern breeds of pigeons as well as in chickens, hardly a natural trait, more like a modification of the foot in the direction of a wing as Darwin observed in his description of the Trumpeter Pigeon, "Their feet are so heavily feathered, that they almost appear like little wings.", not quite as prescient as I remembered it.

Feather footed chickens are much the same in the development of useless quill-like flight feathers growing laterally from the sides of the shank and the middle and outer toes. The genetics is complex, more than one dominant gene being suggested along with inhibitors to leg feathering noted in some stock. Most likely the common concurrence of brachydactyly (shortening) of the outer toe and the quill-like foot feathering and the frequent syndactyly (webbing) found between the middle and outer toes is an indication of some malfunctioning developmental or hox controlled gene. The foot is literally being modified into a wing.

This foot of a Brahma chick illustrates both brachydactyly and syndactyly. The outer toe on the right in this picture is normally slightly longer that the inner toe. In this case it is slightly shorter and the webbing between outer and middle toes more pronounced than usual.


What Serebrovsky discovered and what made me take a closer look was a recessive form of foot feathering that enveloped the tarsus and was largely confined to the shank, not the toes, resembling the shank feathering found on many grouse species.

Serebrovsky calls this the Pavloff type of foot feathering after an extinct Russian breed of fowl. The feathering is more symmetrical on the shank or tarsus as compared with the "Cochin type", the wing-foot, and the feathers are soft and downy, not quill-like. I see this as a natural trait in the flightless Malayoid, the shank covered with small soft feathers except for the rear or ventral side and the toes completely bare.

This recessive trait commonly occurs with and is obscured by the wing-foot. It can be recognized in these cases by feathering on the medial or inner surface of the shank that stops abruptly at the toes.

Here I have managed to isolate the grouse-foot type of feathering to a reasonable degree.

There is one other factor to consider, another recessive character known as the vulture hock, which can be seen in Serebrovsky's illustration above in a reduced form. These are stiff contour feathers in line with the lower leg segment known as the tibiotarsus in birds and projecting beyond the hock joint where the tibiotarsus meets the metatarsus, the shank. Interestingly, these vulture hocks appear to have had a functional purpose in the Malayoid in that they project rearward when the bird squats down enveloping somewhat the rear of the bird.

Thus....

See what I mean?


There has to be a connection between the grouse-foot/vulture hock complex attributable to the Malayoid and the inappropriate wing-foot, perhaps something to do with the transition from scales to feathers.


References:
Darwin, Charles. 1875? The Variation of Plants and Animals under Domestication, Volume 1, Chapter 1.V. Domestic Pigeons, pg 123.

Serebrovsky, A. S. The Genetics of the Domestic Fowl. Part II. The Genetics of Leg Feathering. Memoirs of the Anikowo Genetical Station, 1926.
Abstracted by L. C. Dunn from the translation of B. F. Glessing (The Journal of Heredity, 20:111-118)

The Beard and Muffs.

Beard and muffs are inherited as one unit. It consists of a feathered throat and pointy (sometimes) tufts that are positioned just forward of the true ear on the head.

This is another of Arthur O. Schilling's illustrations. Crest and beard are inherited independently of each other.

Dr. Hutt has little to say about "Muffs and Beard". He considers it an incompletely dominant trait, Mb, because of variable expression in the heterozygote (pg. 129 Genetics of the Fowl, 1949), controlled by an autosomal gene. I say it simply depends on what kind of chicken you introduce it to. If you introduce it to a predominantly Red Jungle Fowl type of breed and you get something rather odd.

The bird on the left is my own, a cross of a White Leghorn over an Ameraucana hen. The picture on the right is a champion Salmon Faverolle pullet belonging to a friend of mine.

              On an Asiatic/Oriental breed it appears much more natural.

The beard covers the throat smoothly like the feathered throat of any other bird. This may be related to a feather characteristic known as 'hard' feather as opposed to 'soft' feather. The difference between the two is in the angle at which the feathers emerge from the skin.
"Hard feathered breeds such as the Old English Game, Modern Game, Aseel, Cornish, and Malay have feathers that emerge from the skin at a low angle and thus lay tightly to the body. Feathers of this type are usually shorter and more brittle and snap like a spring when raised. Soft-feathered breeds have soft fluffy feathers that emerge from the skin at a much greater angle and thus give an appearance of openness...."

"When crosses have been made between hard and soft feathered breeds, many investigators have found that hard feathering is dominant (Jull, 1940).... The gene symbol Ha is proposed for this (single) gene."
(R. G. Somes, Jr., pg 178, Chap. 6 of Poultry Breeding and Genetics, R. D. Crawford, Editor)

So here you have two characters that mesh, two puzzle pieces as it were; feathered throat and angle of feather.

The 'muff' portion of the beard and muff appears as tufts in hard feathered birds and serves to hide the true ear (ear opening is covered by stiff auricular feathers) and ear 'lobe' or ear 'lappets' below from the front while not obstructing vision.

This raises interesting questions as to how these birds fed. Why would the bird's appearance be masked from the front and below by both crest and beard?

Reference

Jull, M.A., 1940. Poultry Breeding, 2nd ed. John Wiley and Sons, Inc., New York.

The Crest....

Crest was one of the first traits which I recognized as belonging to the Malayoid back in 1985. It is generally considered monstrous, a deleterious mutation, reaching it's full expression in breeds like the Polish.

In these birds it is always associated with a bulbous cerebral hernia and a very reduced duplex comb, also known as 'V-shaped' or 'horn' comb.

[ Picture by Ralph G. Somes, Jr., Chap. 6 of Poultry Breeding and Genetics, R. D. Crawford, Editor ]

According to Dr. Hutt, pg. 127 (1949), "It was pointed out by Tegetmeier (1856) that in the skulls of crested fowls the cranium is vaulted, sometimes forming a great tuberosity in which lie the cerebral hemispheres of the brain. The underlying cause of this abnormality was shown by Krautwald (1910) to be an excessive accumulation of fluid in the brain. It fills the third and fourth ventricles and thus causes an upthrusting of the cerebral hemispheres and of the frontal bones which overlie them. The cerebellum lies back on the medulla instead of up toward the hemispheres, and the latter are elongated."

"As a result of these abnormalities, chicks severely affected show at hatching varying degrees of cerebral hernia recognizable by enlargement of the skull and often detectable by palpation. The frontal bones are raised at the posterior and interior borders. As the chick grows, ossification proceeds in the membranes of the fronto-parietal region. In mature fowl the brain is completely encased, but the roof of the cranium is perforated with holes of various sizes. These are less evident in the oldest birds."

"Just how these abnormalities cause the elongation and erection of the feathers that form the crest is not clear, but since the size of the crest is directly proportional to the extent of the abnormalities in the cranium and in the brain, there can be no doubt that the latter do cause the crest. Krautwald found the skin underlying the crest to be thickened and highly vascularized, conditions which could affect the activity of the feather follicles."

[ Illustration by Arthur O. Schilling from the The American Standard of Perfection ]

It is controlled be a single autosomal dominant gene. I reasoned that perhaps this character would take on a more natural appearance in a breed more like the Malayoid such as the Cornish. I found this to be the case, particularly in the hen, although herniated individuals continue to show up.

This hen has a natural crest, no cerebral hernia. Also has a cushion comb and 'beard and muff' traits. She is half Dark Cornish Bantam.

This is a good case of where the breeding shows me things I wouldn't know otherwise. Just because the Malayoid and the Red Jungle Fowl had compatible genomes doesn't mean that the individual traits would necessarily express the same way in the hybrid.

These are full sibs of my own breeding. The chick on the left has a herniated cranium while the chick on the right does not.



References:

Hutt, F. B. 1949. Genetics of the Fowl. pg 127.

Krautwald, F. 1910. "Die Haube der Huhner end Enten. Ihre Ursache, Entatehung und Vererbung." Inaugural Dissertation, zootech. u veterinar. Institut, Universitat Bern.

Tegetmeier, W. B. 1856. On the remarkable peculiarities existing in the skulls of the feather-crested variety of the domestic fowl, now known as the Polish. Proc. Zool. Soc. London, 1856: 366-368.

Why are most Asiatic Games too big???

I had mentioned earlier that the original Malayoid could not have been as large as most of the Asiatic Games of today. One exception possibly would be the smaller Aseel breeds from India which weigh in at four pounds or under. they also tend to be among the longest lived of all chicken breeds.

This is one in my possession. He is three years old now and doing very well. The larger breeds seem not to stay in prime condition for very long as I understand it.

They can be anywhere from six to twelve pounds in weight. The biggest tallest Shamo can reach thirty six inches in height. The most telling evidence that this is too big, from a physiological point of view, is the sparse feathering of most of these breeds and an actual reduction in the size of the individual feathers.

The saddle feather on the right is from a Malay fowl. Even after 150 years in England the feathers remain small.

In the growing chick the retarded feather development is even more striking.

This bird is nearly eight weeks old. Apparently under domestication the metabolism remains that of a smaller bird. The larger size brings the bird very close to it's physiological limit. It can't shed body heat fast enough, so it compensates by reducing it's feather insulation. Heat stress can easily be fatal.

Why brows....

The most obvious answer to why the Malayoid had such well developed brows is that they served to reduce glare much as our own appear to do.

Glare from a bright light source, such as direct or reflected sunlight, causes a reduction in contrast between the task (that which is being looked at) and the glare source. Disability glare is often caused by the inter-reflection of light within the eyeball. (Wikipedia)

The eagle and most other raptors also have a prominent brow ridge that gives them a distinctive stare. The Asiatic games are said to have a cruel look, a bit of anthropomorphism, as a bird cannot change it's expression like a person. Perhaps the intense stare of anger in humans serves to improve vision by lowering the usually dark eyebrows which would serve to reduce glare and increase the contrast of the object being stared at!

It must serve an important function. In raptors it would appear to be related to their need for visual acuity from a great height in bright sunlight. Perhaps the Malayoid also searched for food under bright sunlit conditions. The Red Jungle Fowl is a graminiverous feeder, like most chickens, doing more intense scratching with their clawed toes than other pheasants, picking out tiny seeds and other particles of food. They also put away a fair amount of grass and forbs and have no hint of a brow ridge whatsoever.

It is very possible the Malayoid was more carnivorous in it's diet. Many domestic fowl can and do develop a taste for flesh.

The Malayoid fowl had a strong "delta" beak, possibly designed to crush insects or crustaceans.

 This is a North Indian Kulang fowl. Note the heavy beak and the fleshy skin growing out over the proximal portion of the beak. Malayoid would have had an even shorter more rounded head with almost no break in the curve between skull and beak. Note the exposed conjunctiva in front of the eye often seen in common breeds. This tells me the head must have been shorter.



Here's another one:

 This is Sadie, a very strange Shamo hen. No exposed conjunctiva here.



And one more....

Note swollen cheeks, common in these birds.

So what do you think these birds ate?

A question for you....

I can see where this is going. Been there, done that. The purpose of my blogging is two-fold; 1) To get the word out there, and 2) Get some feedback, some interaction.

Also, these things I know, info I take for granted, may end up losing some of you without my realizing it, unless I explain it carefully. If I am unclear, tell me and I will try to make it more understandable.

So, to make this a little more interesting, a little more fun, here is a question for you.

Why do you suppose the Malayoid has such developed brows? A hint; it resembles a bird of prey.

 From this, assuming the original Malayoid derived from a 'normal' Jungle Fowl....

To this: 

For comparison....

Give it your best shot, and thanks!

Learning by breeding.....

Breeding is for me a creative art form. It is what I have always wanted to do. I enjoy paying close attention to minute detail, part of that fascination I have always had with the fowl. In fact the breeding of specific matings has, for me, become the equivalent of lab and field work for a scientist.

Breeding is not quite the same thing as genetics. Genetics seeks to understand the processes of inheritance and development, while breeding seeks to modify an organism with specific preconceived goals in mind. My work takes in elements of both. I seek to understand genes that belong to the wild-type, in the case of the chicken, two wild-types, with the goal of re-creating the unknown wild-type in it's entirety. That's right, I want to create something that went extinct at the dawning of civilization, a regular Jurassic Park.

Sound impossible, does it? Well, maybe, but it's been a great motivator. And I'm sure to develop at least a very close approximation if not the exact creature. With the breeding I learn more with each generation, gain a more nuanced understanding, which modifies my goal somewhat. The way I like to put it, The more I learn the closer I get, and the closer I get the more I learn. I am not so concerned with the minutia of the inheritance as with what would make the most sense in a natural creature, would recreate a natural balance in form and behavior.

As an example, it's not too much of a stretch to consider the Red Jungle Fowl a flyer and the Malayoid a flightless runner. So what would you be looking for? The Jungle Fowl would be light for it's size with hollow wing and leg bones, a light frame, and capable of very swift flight. The Malayoid would be comparatively heavy for it's size with marrow filled bones and massive thighs and that's what we find in the Asiatic games.

 

 This is a Great Indian Aseel cock. As an example of balance I will point out that these Asiatics often carry their wings out laterally from the body. I learned from my Saipans that this trait allows the wings to cover the massive thighs and long legs. It looks odd, but serves a purpose, so must be part of the Malayoid phenotype.

                                                Thank God for pictures.

I would expect the back to be rounded somewhat, emu-like, in a running bird. Many Asiatic Game have an unusually upright carriage which I do not consider natural. The Red Jungle Fowl, on the other hand, does have a straight back.

Perhaps the best take home lesson here is to get to really know your birds. It would probably be good for every student of poultry science to, at some point, care for his or her own birds, shoulder the entire responsibility for say a year or so, for the productive lifetime of the bird.

The thing I admired most about Dr. Cole was that he actually did the hands on care for all the birds at Cornell, was a very practical man. In fact the university kept him on long after retirement for the express purpose of caring for the college poultry stocks.