2015 Breeding Plans:
I spent most of the evening researching the genetics of split wing. This is my current understanding of it and I hope more experienced breeders can confirm or correct my thinking here.
For newbies, a pretty good intro to the genetics of split wing can be found here:
https://willowcreekfarm.wordpress.com/2013/07/23/the-genetics-of-split-wing-part-1/
Basically split wing is a recessive gene that is not always apparent but can be expressed if two carriers of the gene are mated together. It can spread though your flock pretty rapidly, so the recommendation is usually to cull all birds with split wings as well as the proven carriers, to avoid problems in your breeding program further down the line.
Since I used a single pair mating last year, I can determine pretty certainly that the hen used was a carrier (Rr) with normal appearing wings, and the cock was also either a carrier or affected (Rr or rr.) I no longer have him so I cannot check, but I'm pretty sure he was affected due to the percentage of offspring showing visible wing issues. (Missing it then was my beginner mistake.) In any case, to be on the safe side I have to consider all their non-affected offspring to be carriers.
I really love the look and vigor pullets coming out of my carrier hen and am not prepared to scape her whole line. I do have a cockerel from another line that I was planning to cross into my stock this year, but before I do that, I need to verify that he is not a carrier himself. To that end, I am going to use an affected split wing pullet (rr) to do some test matings. If he is normal (RR), their offspring will all have normal appearing wings but be carriers of the gene. If he is a carrier (Rr), some percentage of their offspring will show split wing.
If the test matings prove the new cockerel is normal (RR), I will go ahead and breed him to the carrier hen and her 2 pullets (Rr). This should result in 50% normals and 50% carriers, but no affected. I will then take any likely breeding pullets from those pairings, and pass them under the split wing cockerel (shown in the photos above) for more test matings to determine which is which. At that point I should be able to cull all affected and carrier birds, keeping only proven normal birds, and move forward.
So my original setting up family lines/rotational breeding fantasy for 2015 was tossed, and I will be replacing it with single pair test matings. With any luck (and great record-keeping) I should be able to remove the split wing from my flock by next spring.
