What about chicken breeding?...So would the chicks from a BR Roo and BO hen be either one of those breeds?- a potential mix?- or always Roo genetics, maybe? How does this work?
I eventy want to get more into selective color breeding, but need to first understand how the basics work.
Basics:
When you cross two chickens of the same breed, you get more of the same kind.
Example: Buff Orpington x Buff Orpington = Buff Orpington
When you cross their offspring, you still get more of the same kind.
When you cross two chickens of different breeds, you get a mix, also called a mixed breed.
If you breed those mixes, after they grow up, their offspring tend to be quite variable. They will show traits from either parent breed, and some traits that were not obvious in either one of the original parent breeds.
Here is an example with real chicken breeds:
You can cross a Rhode Island Red rooster, with a Barred Rock hen. This gives mixed chicks.
This particular mix is so common is has a specific name, "Black Sexlink." You can tell the gender of the chicks by their color & markings. Females will be mostly black, while males will have a light dot on their head. As they grow up, females will stay mostly black, while males will have white barring across the feathers.
If you breed two Black Sexlinks together, you do not get more Black Sexlinks. Instead, you get some chickens that look like Rhode Island Reds, and some that look like Barred Rocks, and some that look like Black Sexlinks (but the colors/genders can go either way, so not actually sexlinks), and some that look like Delawares, and some with other appearances.
If you look up photos of Delawares, they do not look much like Barred Rocks and they do not look much like Rhode Island Reds. But you really can get that color using some genes from Barred Rock and some from Rhode Island Reds!
when your breeding for specific characteristics, is it just selective breeding between two with the traits you want, and crossing fingers for the results?
Yes, that can work.
But people have studied chicken genetics quite a bit, so for many traits you can make useful predictions about how to get what you want.
Here is one site that talks about chicken genetics:
http://kippenjungle.nl/sellers/page0.html
There are several pages of discussion, in various levels of detail.
The last page has a listing of chicken genes, telling what they do and which alleles are dominant over which other ones.
http://kippenjungle.nl/kruising.html
Here is a chicken calculator, where you can put in some genes and watch the image of the chicken change, and you can tell it to figure offspring from chickens of two particular colors.
That site has quite a few versions of the calculator, some with more options than others.
This version is a lot more complex:
http://kippenjungle.nl/breeds/crossbreeds.html
The basic method for figuring out what you will get when you cross chickens: work it out for one gene at a time.
Here is part of how I would work it out for Barred Rocks and Buff Orpingtons:
E is Extended Black, found in the Barred Rock. This is a dominant gene.
E^Wh is Wheaten, another allele at the same locus, found in the buff Orpington.
Locus is the place on the chromosome where the gene is. Allele is the particular form of the gene that this chicken or that chicken has. Some genes have two alleles for each locus, but some have a lot more than that.
Barred Rock E/E (pure for Extended Black)
Buff Orpington E^Wh/W^Wh (pure for wheaten)
Ever chick gets E from the Barred Rock, and E^Wh from the Buff Orpington: E/W^Wh
Since E is dominant over E^Wh, you will see E (black) on every chick.
B is the barring gene that adds white bars to the feathers.
b+ is the gene for not-barred. The lowercase letter indicates it is recessive, and the + indicates that it is the original form found in the wild ancestors of chickens.
Barring is on the Z sex chromosome. Roosters have ZZ, hens have ZW.
Barred Rock rooster is B/B (two Z chromosomes, two Barring genes)
Buff Orpington hen is b+/_ (one Z chromosome with not-barring, one W chromosome that doesn't have any gene for barring or not-barring.)
When you breed them, the rooster gives B to every chick.
The hen gives b+ to her sons, and a W chromosome to her daughters.
So you get sons B/b+ (show barring, carry not-barring)
You get daughters B/_ (show barring, do not carry anything.)
mo causes mottling (white dots on the tips of the feathers.)
Mo+ is the wild-type gene, is dominant, and does not let a chicken show mottling.
Barred Rock and Buff Orpington are both Mo+/Mo+
Since they are both pure for not-mottled, the chicks will also be pure for not-mottled.
So you can ignore the mottling gene when figuring what offspring you might get.
Likewise, you can ignore the genes that cause feathered feet, and the genes that cause other comb types, and the ones that cause green or blue eggs. Parents of these pure breeds should be pure for the genes that cause clean legs, single combs, and not-blue eggs.
And so on and so forth for all the other genes that are involved in a cross, or at least the ones you care about.
Edit to add:
I understand human genetics, biology, punnet squares, etc. What about chicken breeding?
You can use Punnet squares with chicken genes, too.
