Comb genetics

[Amer]

I was hoping for a lesson on genetics from you.
I need to get back to yellow and only yellow shanks.

Oh, I was thinking you meant with a homozygous w/w i+/i+ rooster, but if he was heterozygous for the i+ gene, that would make sense.
Well, there would be only a fifty percent chance, but if the rooster was heterozygous for slate shanks, some of the pullets would have slate. What I don't understand is how you got a hen with slate shanks, as opposed to willow, since white is dominant over yellow. Are they crossbreed? Blue Leghorns project... or something else?

 

[The Moonshiner]

Everything was pure.
Silver duckwing leghorn rooster over blue andalusion hen.
Only hatched three pullets and shank was same color as mother.
Crossed those pullets to a different leghorn rooster hatched two pullet chicks. Both also have same dark shanks.

 

[Amer]

The easy fix is to breed yellow-legged female offspring to a cock that is unrelated, or a relative from the generations before you made the cross -assuming that you did. You don't know what the roosters may carry but the hens are pure for yellow if that is what you see.
Unfortunately, if on the dominant black base, black markings can spot the dermis of the legs heavily, like when my d'Anvers hen jumped in the blue Wyandotte pen. The legs look slate, but if you look at the epidermis, it's actually white.


***This was written before I saw your reply***

 

[nicalandia]

Any of the chicks have dark legs? That would point to EE mother.

The OP mentioned that the mother was an EE and father was CL, If the EE mother had willow or slate shanks(as the majority of EEs have but not guaranteed) That would mean that any result from such a cross would inherit their sire sex linked dermal inhibitor gene Id(Id/- for pullets and Id/id+ for cockerels)

There are a few genes that restrict/inhibit the expression of Id on chicks so this is not always the case. I will go into details at a later time as I have run out time right now

 

[nicalandia]

The legs look slate, but if you look at the epidermis, it's actually white.

I agree, in Extended Black breeds it's actually very hard to have clear clean yellow shanks(non-barred extended black ofcourse), that's why you don't see many Black Plymouth Rocks with bright Yellow shanks.

The same happens on Black Sexlink hens, they are supposed to be Id/- from RIR father but due to Extended black inherited from Plymouth Rock father. You would think they would have the cleanest yellow shanks as both of her parents have such(RIR and Plymouth Rocks)

 

[The Moonshiner]

So what would you get from a yellow skin, yellow shank duckwing rooster over a white skin, slate shank blue (extended black) hen and why?
What about when crossing F1 pullet back to yellow skin, yellow shank duckwing/extended black rooster and why?

 

[Amer]

So what would you get from a yellow skin, yellow shank duckwing rooster over a white skin, slate shank blue (extended black) hen and why?
What about when crossing F1 pullet back to yellow skin, yellow shank duckwing/extended black rooster and why?

The first would give you slate shanks.
The second would give you some cleaner yellow legged cocks. I've noticed even in the blue Wyandottes that the cocks have cleaner yellow legs than the hens, which often have black markings. It may be something you can never avoid.