Why are people concerned about breeding out certain traits that are not deemed in crosses?

[Drumming feet]

Hello all. Hope you're having a lovely Sunday. I have studied older breeds and tried to obtain eggs of some old breeds that used to be crossed to make newer breeds. I wanted to specialize in it, though I'm taking in what I can to insure the genetics are very diverse, observing and planning. I would like to be slow with this, keep chickens natural and in good works. For example I have hatched some langshan from two breeders now in hopes of breeding new and Hamburg, Hedemora are on the way, Australorp/welsummer cross to name a few. I had really wanted to aim at getting some original breeds..

People are concerned with the cross breeding. Why is there so much of breeding crosses as to: older breeds vs newer breeds or just letting nature take it's course, is what I'm wondering here. Arent these breeds very line bred already? What is the point to keep buying from hatcheries when all are possibly line bred?

is it bad to mix an old breed that is already from the new cross back in to it and what would that be called?

Should we outbreed traits like flightiness, temper and limited quantity, as unbeneficial trait?

For breeds like appenzeller spitzhauben that came here by little from a war escapee that have been line bred, should we look for better quality from other sources and leave the old lines take their course?

 

[DarJones]

Your questions infer a need for a good genetics course. New breeds (defined as a stable line that reproduces the selected traits) can easily be made by crossing two different breeds. The further the traits are apart, the more diversity will be present in the offspring.

Crosses are often made to benefit from heterosis. In my experience, F1 crosses tend to be healthier, grow faster, and produce more eggs than stable breeding lines. F1's do not produce true to type so it is necessary to make the cross any time new individuals are needed.

Here are a few things to look up that will help with your questions.

1. Line breeding
2. cross breeding
3. back cross breeding
4. recurrent parent breeding
5. introgressing traits (Look up "introgression" to find the definition)
6. four way cross
7. stable breed
8. inbreeding
9. outbreeding

There are tons more, but these give a good start.