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Genetic diversity in the backyard flock

Posted by johanna_h Z5 SW MI (My Page) on
Tue, Mar 18, 08 at 18:52

OK, it's a simple question, really. How does one improve the gene pool when you only have 15-20 chickens? I have one rooster and 14 hens. Do people trade roosters with their neighbors in order to avoid too much inbreeding? I only have one hen that is from this rooster, so I'm not desperate, but doesn't the time come when there should be an adjustment to the gene pool?

--Johanna


Follow-Up Postings:

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RE: Genetic diversity in the backyard flock

The results would have much to do with your selection priorities. what would be your end goal, more eggs, faster growth, better conformation? The more selection pressure you apply, the slower would be the progress. If you merely wanted to shoot in one direction, you could make faster progress.

A sample of using your flock as a breeding nuc could be ;

make 3 seperate female lines by putting 1/3 of the females in each seperate pen; add 1 male per pen; each year move the male to the next pen and retain the best females of each pen returning them with their dams. Females always stay together, males are the only ones to move. This way there are no sibling matings. programs similar can and do go on for very long periods of time. It is in breeding but not sibling mating. I have birds which are inbred over 35 years, my beagles were inbred since 1952. The larger the numbers you begin with the larger the original gene pool.

Selection is the key to improvment and it must be ruthless or there is little reason to even begin. Most people are gung ho at the beginning but most fail due to lack of a end goal and being in a hurry. They just move on to another breed or hobby.

you could trade roosters or hens regularly but that would probably never show improvment, all you do is swap in more bad alleles either lowering chances for improvement or remaining static.


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RE: Genetic diversity in the backyard flock

That's interesting. My concerns are mostly health, I suppose. I am not interested in showing chickens, or even particularly in keeping breed lines.

My small flock is for eggs and entertainment. I just don't want to have them become unhealthfully inbred.

But I see your points and I'll have to give that some thought.

Thanks.

Johanna


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RE: Genetic diversity in the backyard flock

You can just keep as many as practicable, let them random mate amongst themselves and they will survive, and even possibly do well, for many years. Eventually you will notice a certain color variety becoming more prevelant and the size will diminish. All animals left to their own devices will tend to revert to wild type.


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RE: Genetic diversity in the backyard flock

Swapping roo's is a good idea, or putting your old roo in the pot and getting a new one, or a couple new ones. People are always trying to unload extra roosters -- they can usually be had for free.

Johanna, you are on the right track here. Your concern for keeping heterozygosity in your backyard flock is spot-on.

Flock/herd improvement and maintenance of healthy genetic diversity is traditionally done by rotating in new herd sires, every year or every two years.

If I were you, I'd just refrain from hatching eggs from the one daughter of your current rooster. When you have a number of layers that are his daughters and want to let them set, bring in a new rooster, and let the hens start setting a couple months later.

Don't keep any of your hens' male offspring for breeding. Eat, sell, or trade them.

That's the simplest "system" to preserve the genetic vigor of a small backyard flock.


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RE: Genetic diversity in the backyard flock

Every now and then I like to get some fertile hatching eggs from another chicken owner, or trade fertile hatching eggs with them. Guaranteed new blood! :)

Velvet ~:>


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RE: Genetic diversity in the backyard flock

I disagree with the post suggesting swapping males or the need for new henetics avery few years. The very best way for improvment is not by bringing in random genetics but by proper selection of a well thought out inbreeding plan. Random genes are just that, random, now way to improve by just swapping genetics.

Bringing in a new female would be more sensible tan a nre male. The male will influence all offspring, good or bad, a new female line will only influence her offspring allowing for a more balanced view of improvement or back slide.

it really will make very little difference in the average back yard chicken project. breeders of top quality poultry have different needs than backyarders.

My best birds over the last 4o years for health and type have been inbred, those who keep swapping birds normally make small progress if any at all.


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RE: Genetic diversity in the backyard flock

fancifowl, you are indulging the hobby of breeding strictly ornamental birds to win shows. Presumably utilizing a rather intensive husbandry system.

Johanna's goal is to maintain the genetic health of a backyard laying flock. She stated what her goals are, and are not, quite clearly. She has rightly identified that part of that requires avoiding obligate sire-daughter inbreeding, particularly across multiple generations.

Why insist on substituting your goals and values for hers?

Desirable flock heterozygosity is most simply and effectively maintained by replacing the flock sire when the laying hens are the daughters of the current flock sire.

I agree that selection is crucial, whatever one's goals. One must cull. If you practice selection effectively (and only so rigorously as one's goals require), the best way to maintain genetic health of the flock is via assortative mating, not inbreeding that requires much more aggressive culling of animals homozygous for defective genes.


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RE: Genetic diversity in the backyard flock

I did suggest that mediocrity could be mailntained for a long period by random matings amongst an originally mediocre group. good breeding doesnt only apply to enable selection of show qualities, obviously it is used to maintain and improce herd/flock health. I no longer breed for show but I do intend to maintain a high degree of health and vigor in my flocks, the best way I have found is by elimination of any animal which exhibits untrift conditions, usually by killing. I never breed an animal which has ever been sick. This and inbreeding the besat to the best has given flocks which never show illness.

Bringing in a new male at random may allow for disease or low fertility or any other deleterious element to enter the breeding flock.

Even a simple backyard group of animals requires some kind of breeding plan, it is relativly simple to meet minimum requirements of healthy breeding. poultry can withstand a great deal of random mating without noting much deterioration in over all health & vigor for some generations. I just fail to see the fault in trying to encourage keepers to become more successful and knowledgable in their hobby/pursuits. To some ignorance is bliss, I am aware of that fact.


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RE: Genetic diversity in the backyard flock

I know nothing about breeding farm animals. I grow tomatoes, but I buy the seeds.

Nevertheless, this subject has always intrigued me. Recently, we obtained a pure-bred Golden Retriever (amazingly, from a pound), and I was quite fascinated by a book given to us about how this breed was developed. It got confusing, though.

Why am I writing here? To obtain a comment from obvious practitioners on something that was told to me 20 years ago, that I have never delved into.

20 years ago, I happened to speak to a man who was about to retire from his work, and his ambition was to "go back to the ranch." He wore a string tie regularly, even as he worked at Hughes Aircraft, which belied his sentiments. Maybe it was the tie that caused me to inquire with the man.

He said he was going back to breeding cattle. What he told me shocked me... that a good bull would be bred over and over again into its daughter line. (That's my wording, not his.) But I recalled that he said that a good bull could produce a daughter, and that daughter would then be mated to the same bull. On and on, with granddaughter, great-grandaughter, etc. The objective was to get offspring for the slaughter (I presume) that were very similar to the bull.

Of course, as a layperson, the notion of inbreeding depression left me incredulous. But he said that was a problem with people, not cattle. I have believed him, ever since, though I have never corroborated his advice elsewhere. So I am seeking corroboration, after all these years.

I happened upon this forum for other reasons, so I consider it quite fortuitous that I have discovered this thread.

Over the last few years, I have grown tomatoes, and read about tomato horticulture, and have been told that inbreeding depression is not a problem with tomatoes.

But I keep thinking about that mythical prize bull that my friend with the string tie described to me. Was not that bull the beneficiary of heterozygosity? It just tells me that dehybrizing a bull is a crap shoot. And considering the size, and gestation period of cattle, that is a long term gamble.

So I appeal to those who have walked this walk to comment.

Thanks


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RE: Genetic diversity in the backyard flock

Imbreeding can be good and useful to a point, however, there are problems. The repeating of the same genes over and over again can cause longterm issues that the breeder would know nothing of. For emample, there is a certain type of dog (I will not name) that has been inbred for so long that the breed now has serious issues (aggression) that are believed to be in the brain due to the lack of genetic diversity.

Another example is also a good example of bad animal husbandry. A certain ranching family has kept the same breeding stock for four gererations (of humans, since 1910?). This breeding stock, horses, has always been bred father to daughter, and maybe brother to sister/mother, they did not keep very good records. Anyway, their horses are all displaying problems from the lack of genitic diversity. Sure, they are nice looking animals and still look like horses, but there is the albino gene that keeps popping up now which was not in past generations, blindness and their teeth need to be pulled before they are 10 years old.

Sure breeding for a goal is the right idea, however, inbreeding is not the best way to go about it.
I am raising heritage breeds and I am always looking for other breeders in the area to trade stock with to diversify the bloodlines. You have to remember that these breeds were chosen for specific things, ususlly meat and egg production in poultry. I want to keep the genitic diversity for the next generations to enjoy, not limit them to what I think is IDEAL. One man's trach is another man's treasure. What makes you GOD???

I change out my roosters every few years, either trading with another breeder or ordering two or three and picking the best one for the breed, to breed. If he does not do the job, I have a few backups. I can even swap roos a few times in the season and then have soup at the end of the year.

Billie


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RE: Genetic diversity in the backyard flock

I have heard about those who breed the same sire to generations of the female line. I have done it. breeding rex rabbits in the 70s I usedf a certain superior male on 7 gens of his female progeny; I culled as best I knew at the time and produced a very good line which were super show animals. but i neglected to do a total study of traits and ended up with thin hock pads. I was ready to reach out for near relatives when a dog attack solved my breeding problems for me.

I have for 40 years bred very close in all of my stock but have learned to cull severly and to evaluate the total animal. I work with a poultry scientist and a poultry geneticist as mentors and partners and rely heavily on their opinions while i do make the final decisions. my Sumatra line of bantams has been inbred for nearly 40 years now, my black Hamburg bantams, which we made from the ground up are totally inbred. both lines are superior in the show room, the Hams are super egg producers and health is top shelf. nearly a 100% hatch rate in the Hams and excellent with the Sumatras. No new or outside genetics in 10 years now, its a captive flock.

My beagles were bred very close too, never a mating w/o " little Man" at least 2 times in any 7 generation pedigree. They just keep getting better.

I never inbred my horses but my Scttish Highlands were inbred to some degree.

My belief is that inbreeding is the best method of breeding to eliminate the bad genes. It does take a great deal of paper work and study/observation. dealing with larger animals is a harder game due to monetary value and time involved. A outcross to a totally inrelated animal or another breed will give momentary flushes of qualities such as rate of gain, milk production or vigor but a decrease is noticed in suceeding gens without a well managed culling criteria. A study of the holstein breed will show that many of the high producers are closelu related.
No one should be afraid of inbreeding but it does take a great deal of study and mistakes can be very noticable. In all of my breeding of animals, the only monsters I have produced were from total outcrosses; inbreeding depression is seen in several ways, poor health, less milk, fewer eggs, lower sperm, and so on but it neednt be a severe problem if culling is properly practiced.

I would say the easiest and probably the best way for average backyardes is to not inbreed until they are ready to reach a new level of study; a competent mentor is a great asset too. I have realized my share of mistakes but that is what makes me want to do better.


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RE: Genetic diversity in the backyard flock

Thank you for the fascinating replies.

Fancifowl, you said a "dog attack solved" your "breeding problems." I am wondering what you meant... Are you being facetious, or serious? It sounds like a dog killed your prize breeders. Please tell me what happened.

40 years of your experience is highly appreciated here, even though I doubt I will ever breed animals. But I have kids with a flair for science, and I hope to educate them beyond my own personal levels of expertise!


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RE: Genetic diversity in the backyard flock

2 dogs tore the hutches to pieces and killed my rabbits. I dont remember just how many but it was the majority. I did receive reimbursments for the pens and stock. The owner of the dogs originally wanted to contest the values I put on the animals( $50 ea. for the 2 bucks and 2 does, each with 1 or 2 champion legs and $25 each for the younger animals and as I recall about $75 for the pens. It was a pretty healthy penalty for allowing his dogs to run. When I gathered a few testimonials he paid up quickly. This was in 1976, I think.

I am currently having problems with a new neighbors dog, I explained the values of my birds and rabbits and hope he is making a good effort to control his mutt. I have told him I will shoot to kill if it ever comes on my property again.

I have culled my poultry selecting for resistance and just dont have sick birds any more; I have not really put that emphasis on the rabbitry, yet. But as I begin more intense inbreeding I will no doubt have to select for resistance or will run into some problems. I do use outcrossing in the pheasants, as much as is possible. Most of the caped pheasants are pretty closely related even with the new imports of several years ago.


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