The Genetics of Split Wing – Part 2

Be sure to read Part 1 first as it explains how the genetics of an autosomal recessive gene like split wing can play out in different matings.  And it shows how I am using the letters R and r to represent the different genetic options for the trait.

Here I am going to discuss how it can affect our breeding program.

Some of the chicks we recently purchased are actively showing split wing.  So they have the genetics rr for split wing.  After learning about this we checked our whole flock out and found that 3 out of 4 of our adult Rhode Island Reds have what I think is a form of split wing, where the feather is not missing, but it is much much shorter than the others, thus looking very similar.

We do not want to continue split wing in our flock and thus clearly we should not breed the chicks or hens that are actively showing it.  BUT, to be conservatively careful, we must assume that any chick that came in that group, and any hen that is a RIR from the same hatch, could be a full sibling to the split wing chicks and hens, and therefore they could be carriers of the gene (Rr).

And actually, putting the new chicks and the RIRs aside, any bird in our flock that isn’t showing split wing (and thus possibly making it into the breeding program) could be a carrier of split wing (Rr) at this point and we wouldn’t know it.

So if we take out all the active split wings, these are the matings that could still possibly take place since we don’t know which are carriers and which don’t have it at all:

103_0527 103_0524 103_0523

If we breed two carriers to each other, that would be the only time that we would for sure know that we have split wing in our genetics because that is the only way that an offspring would show the split wing on its body.

103_0527So if we keep careful track of which hen laid which egg and which rooster was breeding her we could identify carriers only if both parents are carriers because some of the offspring would show the split wing.  If we had a chick hatch that actively had split wing, and we aren’t breeding any parents with split wing, we would know both parents were carriers and could cull them from the program.

However, if one of the parents doesn’t have it, and one is a carrier, and we breed them, we are creating more carriers and don’t even know it until later on in our breeding program when two carriers happen to get mated and it comes out with a chick with split wing.


One way we could purposely test our rooster, to see if he is a carrier, would be to purposely breed him to a hen with split wing (rr) and collect at least 8 eggs and incubate them.  If we ended up with any split wing chicks at all we would know he is a carrier.103_0526If we had no split wing chicks at all we would know he is not a carrier.  However, all of those chicks would be carriers and they, as well as their split wing mom, would be culled.


Using a split wing rooster to purposefully find out if any hens were carriers would be useful as well for culling out the hen carriers.

BUT, either of those options involve a lot of work and time and effort to identify eggs exactly and incubate them through only to have to cull them all.  Is it really worth it to for sure eradicate it right off the bat, as opposed to doing our best to weed it out as we go along while still possibly adding more carriers to our flock?

It is not a fatal trait.  It does not affect their egg laying or meat producing abilities.  However it is not conformationally “right” and it does affect their ability to “fly” when needed.  We would like to breed our birds to be properly built birds with all their working parts, even though we aren’t showing them.

So that is where we are.  We are trying to decide what to do.  Interestingly, a few of the chicks seem to be “growing out” of the split wing as they get older.  A feather is growing in the vacant spot.  Is it possible that some birds just develop that feather later and it doesn’t constitute actual split wing?  I’ve found people online that are in both camps as far as that goes.  But we have noticed that some split wing bird’s wings feel different.  The structure and build of the wing, especially the joint, feels much looser and not “right” compared to the birds we have that don’t show split wing.

We will continue to research and discuss this topic as we try to make a good decision for our breeding program.  We are also keeping a close eye on these chicks as they mature to see what their wings do.  Lastly, we DID add in the one RIR hen that we own that does not show split wing into this week’s breeding.  We actually added her before we knew of any of this split wing stuff because we selected her as having many of the traits we are looking for.  But now that we know about it we realized that she might help identify whether or not our roo is a carrier.  Because if she is a full sibling to the ones that have split wing then she is likely a carrier.  So if any of her eggs hatch and have split wing we will know our current rooster is also a carrier.

Technically, if any eggs hatch that have split wing at all we will know our roo is a carrier and that the hen that egg came from also is.  But it seems to up our chances by putting that RIR in there since the other RIRs she came with have split wing and thus she has a higher chance of being a carrier.

Hopefully I haven’t left you all with your heads swimming with all this confusing genetics talk.  But I find it all very interesting, and it is pertinent to our current breeding program so I thought I would share it with you all.  🙂

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