Usually always females, unless willow legs is a breed characterisic. With yellow legged varieties, a yellow legged male can be a carrier of willow and not show it. You can use a willow legged female in your breeding program, however, I would hesitate to use the willow legged females from an original mating of yellow legged male x willow legged female. Rather, use the yellow legged offspring from this mating, and breed away from the willow legs. Craig, I had willow legs with the Partridge when I had them and you can breed away from it. A couple years ago any partridge chicks that hatched with willow legs were culled and didn't make it to the brooder. Unfortunately, what I also noted is that quite often the better patterned birds had willow legs.
I am getting plenty of willow legs this year with my large Golden Laced (females).
In the non-patterned arena, this year I crossed a Buff Leghorn Bantam male, with White Leghorn pullets (purpose is to improve type on the Buff Leghorns). I got plenty of willow legged pullets from this cross, and they have sort of a champagne colored feathers. Their legs are very green. I did get some yellow legged females too.