Where did these yellow legs come from?

[City Chicken]

I crossed light Sussex and white rock.... Mostly I come out with white legs, although I've come across a few green legs.
What I don't get.... I have a couple with yellow legs.
I did at one time have a cornish x that MAY have laid a few eggs....
So it could be from her.

In chicken genetics, is it possible to have two white legged birds pass on a yellow leg gene?

 

[ramirezframing]

white rocks like all rocks should have yellow legs

 

[City Chicken]

Oh dear, well, then she's not a white rock, what is she???. White chicken, white legs?

 

[ramirezframing]

picture would help

 

[City Chicken]

Even if her legs look a little yellow against my dark blue shirt, they are not, they are white.

 

[tadkerson]

The yellow legs of a hen will turn white after she lays enough eggs. It all depends on the amount of yellow pigments in the food the hen is eating.

 

[City Chicken]

Welll, what im trying to figure out is what breed she is. I thought she was a white rock, but she has always had white legs.