Here is what I wrote to another member...
'I tried to figure out if there was a formula for figuring this out, but unfortunately there isn't, so we'll have to count using our fingers! I'll try to explain it as best I can; it's confusing...
To directly answer your quesion about 2 lines, you would end up continually breeding either 2nd cousins no matter how you did it, which some are comfortable with, but I would rather keep the usuall minimum of 3 breeding lines...
To figure out how closely related members of different lines are, you have to intimately understand how spiral breeding works:
-you must have 3 breeding pairs/trios to start with. (1 pair becomes line A, another becomes B, and another becomes C)
-Then, after breeding them, 'discard' (never let the parents breed again) the parents. All the female offspring must remain in there mothers line, while all the males must be 'rotated' to the next line (A-born males - B-born females; B-born males - C-born females; C-born males - A-born females). Then repeat the process all over again. It's important to always 'rotate the males in the 'same direction (i.e. If you move A-B, do NOT move B-A the next year. That will REALLY mess things up)
So, hopefully you've grasped the concept, so now onto discifering the relations:
Let's say you have three lines (A; B; C). To figure this out, you have to 'follow' a direct male line until a member get's bred to a female from the line at which it started WHILE counting the generations that have passed. Sound confusing? It is. I'll try a practical example:
- A line A hen, and a line C cock (remember this pair) breed and produce pullets and cockerels.
- of course, the cockerels get moved to breed with line B hens, while the pullets stay in line A to accept new cockerels from line C.
- the cockerels that were born to line A are bred to line B pullets (which by this time, both cockerels and pullets would be adults). Again, the new pullets and cockerels get separated. Meanwhile, the pullets that were bred from line A will have been bred as well. So 1 generation = the new offspring are cousins 1X removed between Line A & B.
- the cockerels that were born to line B are bred to line C pullets (which by this time, both cockerels and pullets would be adults again). And again, the new pullets and cockerels get separated. Meanwhile, the pullets that were bred from line A will have been bred once again (these are the granddaughters of the pair I originally mentioned). So 2 generations + 2 lines removed = the new offspring are cousins 4X removed between Line A & C.
- the cockerels that were born to line C are bred to line A pullets (which by this time, well obviously they'd have to be adults now). This is where the 'rotation' is completed. So 3 generations + 3 lines removed - the complete rotation (the cockerels are actually now related to the pullets they're breeding) = the pair that is breeding are cousins 9X removed. So once you've been spiral breeding for a few years, you will always be breeding cousins 9X removed.
(I believe that 4 lines results in about 20X removed cousins, and 5 results in practically unrelated birds!(something like 45X removed))
It definately helps alot if you have a relations table handy. Those are like multiplication tables, but with uncles, cousins, 2nd cousins, common ancestors etc. Perhaps if you can find one, you can figure all this out more accurately. I'm only mentally calculating all this, so it's not quite so reliable, but Spiral breeding does work. Backyard Poultry magazine has an article on there online library that briefly discusses Spiral breeding (aka Clan Mating). Pathfinders farm also has a Spiral breeding artricle on there website.
I know this looks dauntingly confusing, but believe me, the managment of spiral breeding itself is very simple. It's when you try to figure out the relations, that's when it becomes complicated. But overall, it's like long division. It seems everyone can remeber having trouble understanding division as children, but once you do get it, it becomes easy for you to use. If you have any other questions, or still don't understand something, please feel free to ask, and I'll see if I can answer.'