Genetic discussion of slow Feather (K) and tardy feather (t)

[crystalcreek]

Can some of the genetics gurus on here please discuss the genetics behind slow feather gene (K) and tardy feather (t) and whether there are benefits or drawbacks with either.  I also want to know if they can both be present on the same bird.  My application has to do with the lavenders I\'m working on.  If there are serious drawbacks, how is it eliminated.  Here are two pictures of a male/female same age where I believe something is pretty evident (look at the tails) to get the discussion started. The cock is the same male all grown up, to show that the final plumage is normal.

[crystalcreek]

As an aside, this cockerel did not exhibit the same rate of slow tail feather growth.  Is it a coincidence that he is also relatively free of any \"ticking\"--the little horizontal bars in the feathers?  Ticking seems to be a male trait, based on what I\'ve grown out here.

[crystalcreek]

And finally, this is a son of the male in the post at the very top.  A slow tail (but not as slow as I remember on his sire), but no ticking either, hence all my confusion.

[Mike Gilbert]

I am unaware of any reason why Ameraucanas should be anything other than fast feathering.   But at least with the first cock and his son you got some decent width and substance to the tail feathers.  Those of the second cock look pretty narrow.  That may or may not be related to the lav gene, as I have owned black bantams with no lavender blood in them that had the same problem.  

[jerryse]

You can sex chicks by the growth rate of the tail feathers.The pullets tail will grow faster if I remember correctly.That may not be what you have.Was this the only cockerel with this condition?Just thought I would put this out as a possibilty.

[crystalcreek]

You can sex chicks by the growth rate of the tail feathers.The pullets tail will grow faster if I remember correctly.That may not be what you have.Was this the only cockerel with this condition?Just thought I would put this out as a possibilty.

It was not the only one.  From talking with others working on the variety, I believe it is pretty common.  I know several breeds were used to introduce the color in bantams, and subsequent to that, to improve size, so is it possible those were the source, and it is, indeed, slow feather?  Or tardy feather?  That\'s why I want a description of the gene so I can figure this out, even when Ameraucana typically don\'t exhibit either.

[Jean]

From what I have browsed in the Genetics of the Fowl book, tardy feathering does not differ in the male and female birds, so they would both be showing very slow feather growth.

So, in my opinion, what we have is the slow feathering gene.

http://chla.library.cornell.edu/cgi/t/text/pageviewer-idx?c=chla&cc=chla&idno=2837819&q1=Genetics+of+the+Fowl&frm=frameset&view=image&seq=146

[Mike Gilbert]

Sellers website lists a total of four possible alleles at the K locus.  The first, k+ is wild type and rapid feathering.  Then there are three others that cause varying degrees of slow feathering.   The link is listed below.   All are sex linked, which explains why males feather slower than females;  the males inherit two of the K series genes while the female only inherits one.  Also, k+ is recessive to all the other three, and that explains why you can have a rooster that throws both fast feathering and slow feathering progeny.  Such a male is split for k+ and one of the three K slower feathering genes.  

Thanks for the link to the Hutt reference.  Though I own the book, I have never read it from cover to cover - too boring to spend that much time on it.    He does seem to document a good case for an autosomal (not sex linked) recessive gene (t) that acts similarly to the dominant K series.  

http://sellers.kippenjungle.nl/page3.html

[crystalcreek]

Is it something that \"needs\" to be eliminated?  If it is, how does one go about doing that since it would be a sex-linked trait and possibly present as a recessive?  I keep going back to fast feathering blacks but perhaps I am not on the right track.  I hate to start all over again, at this point, because the birds are getting better, in my opinion, however slow the rate of improvement may be (pun, intended).....  Will the daughters of the slow male above crossed on Smith blacks be \"carriers\"?   Please pardon all my questions, I\'m just really trying to understand this.

[Mike Gilbert]

The answers to your questions depend on whether you are dealing with K or t.  Apparently K is dominant and sex linked while t is neither.   So the best course of action is to find out which it is.   So get a female from a known fast feathering line and cross it with your slow feathering rooster.    If half or all the pullet offspring from that mating are slow feathering, you know you have K.   If they are all fast feathering you have t.

[Beth C]

I\'d say if you got a male with no brassiness or barring you\'re headed in the right direction. Every male I hatched was brassy, every male split I hatched had leakage, although one very little, and the females weren\'t much better. I kept 2 pullets & there\'s a 3rd I\'m debating using. I only hatched 2 fast-feathering birds and, unfortunately, lost one of them. The remaining pullet has a single comb but I\'m rolling the dice anyway.

I don\'t know what other people are getting, but I\'m wondering if I\'m dealing with Kn. I got quite a few that looked like this:

http://ameraucana.org/abcforum/index.php?a=topic&t=1560

ALL of mine were very slow to feather, but the worst ones appeared to be male.

I destroyed the majority of them, but kept a couple to observe, and they did eventually feather in fully. But they were literally naked for the first few months. And didn\'t look much better with feathers than they did without.

To be honest, I\'m getting pretty discouraged with the lavenders. My only contribution to the variety this past season was killing about 100 really ugly ones before they could reproduce...

[grisaboy]

The K genes are used a lot in the commercial poultry industry.  This allows them to feather sex day old chicks.  The male parent line would be pure for fast feather (kk) and the female parent line is pure for slow feather (KK).  Because this is a sex linked gene, all of the female chicks will be fast feathered (k-) and all of the males will be slow feathered because the slow feather is dominant (Kk).  This can be seen on the wings of the day old chicks because the females will already have longer primary feathers starting to grow and the males will have little stubby primary feathers. Probably 98% of your commercial layers and broilers in this country use this method to sex day old chicks.  The difference is not really apparent in the plumage of the adult birds.  Especially in the white commercial birds.  It would be apparent in barred birds as slow feathering produces the nice even bars in barred rocks while fast feathering gives the less even barring in cuckoo colored birds.

Curtis

[grisaboy]

There are special considerations that have to be taken into account with the lavender variety.  There are several plumage flaws associated with this variety.  One flaw associated with the lavender color is poor tail formation.  By this I mean that the tail feathers are thin and twisted and never quite develop into the proper full tail of the breed.  I have not seen this too much in the lavender Ameraucanas but it is fairly common in Self Blue Old English Game Bantams.  If you cross these lavender birds with poor tails to blacks, the resulting black splits do not have the bad tails.  When the splits are bred back together the resulting lavenders often will have the bad tails.  It does not seem to be expressed in the female lavenders either.  This means that even if you cull your males ruthlessly for bad tails, the trait can reappear from your females or your black splits.
Another feather flaw associated with lavender males is a patch that appears on the wingbar.  This patch will look like the feathers have started to molt and new feathers are coming in but the new feathers never quite fully develop.  This trait is like the twisted tails (and may be related) and is not expressed in females or splits.
We do not want to have these flaws showing up in our lavender Ameraucanas because they are very hard to eliminate. Lavender breeders should take special precautions and select hard for good feather quality.
Curtis

[crystalcreek]

I personally have only dealt with it in males, working with the stock I have here.  I have not personally seen the trait manifest itself in a female of any color--split or lavender, but I may not have hatched enough chicks for that genetic occurrence to pop up, either.  I do know that the two female splits I raised out of Paul Smith pure blacks that were sired by the slow lavender cock have grown their feathers normally.  I did not raise a male from the cross, but another member has one, and from the picture I saw, his tail looks perfect. I have crossed those two girls on the lav cockerel with what I think is a normal tail (it didn\'t grow slowly, but the feathers are thinner) and I have week old chicks from that cross that I\'ll take a closer look at after the holidays.  I am seeing some tails already in the brooder, so I think that\'s a good sign.  But then again, maybe those are all the females.  Perhaps I should be banding those birds now and keep only those?  I guess I was not expecting females to be carriers since it was a sex-linked trait.  

It sounds to me like there\'s a couple of different things going on with these lavs.  I know it\'s hard to talk about our trash birds, but we have to in order to figure this out and eliminate it!  Beth, thank you for posting those pics of the naked birds!  I have not hatched one like that, but maybe you have a double copy of something and perhaps my birds have been homozygous only and my stock does have the potential to produce one that looks exactly like that.   This is precisely why I want a better understanding of the genetics behind the flaw.

[crystalcreek]

So, back to the question.  Let\'s assume it is K, as Jean has said.  How do we eliminate it?

Can males who exhibit the trait be used if they are crossed on normal females?  I have gotten some lovely females from this cross, but if they are all carriers, we\'re back at square one, which leads me to the next question--

Can females who are daughters of slow males carry the gene hidden?  Does it pass to only their male offspring, female offspring, or both?

I don\'t understand sex chromosomes in chickens, and therefore sex-linked traits are confusing to me.  I really want to, I just can\'t seem to wrap my brain around it.