F1, F2, F3 is just the generations of breedback along a line, any line, but the SAME line. You'll need to keep records.
Parent bred to parent offspring =F1, even year after year. All offspring will be F1.
Parent bred to F1=F2 (keep best)
Parent bred to F2=F3 (keep best)
Parent bred to F3=F4...at this point most breeding books suggest crossing the lines by breeding best F2 to best F4....your line is now set.
For olive eggs, you need start up stock of pure breds for the darker brown genetics from a line such as Marans, Barnevelder, Penedesenca, etc., from one parent side then a pure bred start up blue shell gene from the other parent side, typically Cream Legbar, Isbar, Araucana, Ameraucana, etc.
The genetics for olive is brown wash over blue shell to produce green. The darker the brown wash the more olive the green. How you get there doesn't matter so much with what breed, or even generation, you use but what genes you have in the birds...whether they are pure bred (essential for a start up olive program) or a carefully controlled and proven olive line.
In Olive Eggers, the original OE line begins with something like a BCM bred with a CL or AM to get F1. That produces, 100%, offspring with 1 blue shell gene and some of the genetics for brown shell wash. Unfortunately there are almost 13 genes, some dominant some recessive, some partially, that produces the brown wash. That varies with each offspring and, I find, tends to breed out, so you need refreshing of the brown wash to keep true olive until your line is very established.
The blue shell side is easier to keep. Once you've got blue shell genes faithfully inputted into your line, you simply select blue to green eggs to set since visually you can see that they have at least 1 blue shell gene...otherwise they wouldn't have the blue tones.
Pure blue shell breeds have 2 blue genes. They give 1 gene to each offspring, so a F1 hybrid will have 1 blue shell gene. F1 Hybrid (1 blue gene) bred to F1 hybrid (1 blue gene) produces 25% 2 blue genes, 50% 1 blue gene, 25% no blue gene. So you have a 75% chance of promoting your blue line at F1 (statistically...like tossing a coin...your actual results will vary depending upon number of chicks hatched).
Selecting for color blue-green shells only of the F1 blue line, especially in breed backs to the blue parent, you can eventually get to a point where the majority of your birds likely have 2 blue genes which ensures the blue shell no matter what brown line you breed over them. You've now established blue.
Typically to gain enough breeding stock, breeding F1 back to the original parent on either side reinforces either the blue shell or recoops the brown wash better if bred back to the "brown" wash parent, using only the F1 blue toned eggs to ensure at least 50% offspring will have blue tone possibility with added brown wash....Then you select from those F2 daughters that produce the best olive....carry forward.
In answer to your OE rooster, he can be very beneficial once you figure out what he has under the "hood." Breed him to a white layer to see how much brown wash genes he may actually carry. *Typically* (but not always as you are dealing with hybrids), the brown color of the daughter's egg will be halfway between the dad's and the mother's if you have a dark layer and a white layer. You can determine if your boy has any brown shell genes that way by setting a few of the white layers.
You will also see if he has any blue shell genes. If any of the daughters grow up to lay greenish/bluish eggs, then he has at least 1 blue shell gene. If he throws daughters consistently that lay bluish-greenish genes, then he may be an F2 or F3 OE that has an established 2 blue genes....which is great for breeding....and if you are lucky that he's recooped enough of the brown wash genes to show that his daughters are hitting a mid-tone brown, you've got a keeper.
It takes some investigative breeding to see what a male has genetically, but an OE rooster can be beneficial to keep the blue alive in a line and help refresh the brown.
I keep my Barnvelder rooster for his beautiful, proven terra cotta rich brown colors he passes partially to his daughters. Then I line breed back those daughters (from a Cream Legbar line) to intensify that brown wash.
I have kept one of this F2 hybrid OE sons (actually an F1 parent bred to a different F2 line...so 75% chance blue shell with a good chance of increased brown. I'm using him to breed back with an F1 CL/Barnevelder hybrid OE daughters to insure I will not breed out my blue coloring....and again keeping my original Grandpa Barnevelder to refresh brown. I had kept a really nice F1 son, but sadly an accident took his life, but not before he created his own nice line boy for me which I will use in his place with the assurity I've got 75% chance though this boy of now of keeping blue.
I hope that makes sense. I'll post my chart that I developed with my F1 and F2 efforts. (Note tag on far left of egg box should be F1 for CL/B)....B = Barnevelder roo
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