Inbreeding in chickens

[chickenboy7c2d]

I've heard people say things like, 'sally is john and joan's daughter, and william is sally and john's son' (just an example), sounds like inbreeding to me. Wouldn't it cause some deformed chicks or is it perfectly normal and fine for chickens to do this??

 

[Uzuri]

Line breeding (which is what you're describing) emphasizes traits. That can be a good thing or a bad thing. If you propagate bad traits, it's bad; if you use it to bring out desired traits, it's good. It's heavily used in racehorses, actually, and anything else where you want to "fix" a trait in the line.

Naturally you can also fix bad traits this way; a responsible breeder keeps an eye on such things and abandons lines that are trending toward the bad trait.

Linebreeding and inbreeding are social taboos, but in reality, they actually don't cause as much harm even to human beings as popular culture might suggest -- unless, of course, the original "breeding stock" had a genetic trait with negative consequences. In that case the bad trait will become fixed in the population unless outsiders can be brought in to dilute it. Over time an inbred population loses genetic diversity and consequently the ability to recover from certain disasters (diseases with genetic survival components, changes in environment) and adapt. In chickens, no big deal -- you go to your neighbor who has a different strain and bring some in.

 

[chickenboy7c2d]

That was really interesting, You learn something new every day!

 

[Momo]

Excellent post, Uzuri - well said!

 

[donrae]

My mom taught me if you get a good result it's linebreeding. If you get a bad result it's inbreeding.

 

[woodmort]

Quote:

From my years of working with tropical fish I agree.

 

[spook]

Quote:

From my years of working with tropical fish I agree.

Good one!

 

[Jferlisi]

Its ok to do father to daughter and mother to son but not sister to brother. Good rule of thumb.

 

[mandelyn]

It's fine to linebreed so long as you really know the breeding stock you're working with. It's an issue when a serious flaw is overlooked for the sake of all the good things, such as HYPP in Quarter Horses, and many of the canine issues, and any other species. You need to have genetically diverse and healthy animals to start with before close breeding like that. Adding outside blood every couple of generations.

It without a doubt sets a type, some very noticeable and desirable traits. It's the making of a bloodline, that will prove to be reliable and predictable. It's also used in the formation of new breeds or colors, to make those new traits reliable and predictable.

With chickens not commonly used as "stud" animals, if a flaw in the genetics is found, it hasn't been spread all over the bloodlines of others like with dogs and horses. That's where problems arise within an entire breed, is when one fabulous stud is bred again and again, passing on everything he has, good and bad. It can go unnoticed or ignored for generations. Anyone that "outcrossed" to him to in theory improve their own lines, potentially added a very serious genetic illness, initially not even knowing it until years later and countless animals created.

Culling is the most important part of it, knowing which animals to remove and why. Line breeding willy-nilly without goals is pointless. You only do it if you know what you're looking for. If there is a type you're aiming for, or a new color for a breed, then you need to know who to cull and who to breed back to based on what they produced. You have to make A LOT of babies because there will be A LOT of culls starting out. It can take 4 generations or many more to produce something that will be reliable when bred to another of the same type. Depends on the culling through out the whole process.

 

[woodmort]

One other thing that I'd add: It is important that you keep good, thorough records of each breeding and "tag" the offspring. Nothing can mess up the whole process like losing track of who came from what line and who their parents were.