Shank Color Question and Other SOP Factors

I'm a rookie chicken farmer so my knowledge is fairly limited. I have a single flock of hatchery stock (9 month old pullets) layers consisting of Barred Rocks and White Leghorns. I also have a cock bird (Barred Rock) that I bought from a breeder a few months ago with the intention of playing around with breeding to try to improve the Barred Rocks I have. While I don't have top quality birds to work with I find breeding very interesting so I began construction on a four section breeding coop so I can isolate birds I want to breed and it should be done in another month or so. So in short I'm having fun learning about breeding and hope to go through the process a few times to figure out what I'm doing before purchasing birds close to the standard and getting serious, so that's my background.

I've been reading a lot of books lately about breeding and one of course is the APA's SOP which I bought when I joined the APA a few months ago. One of the standards for Barred Rocks said the shanks have to be yellow or dusky yellow to qualify. My Barred Rock cock has nice yellow shanks but my hatchery pullets have everything from a pale yellow, from laying a lot I'm assuming, to a dark shade of gray-black. I believe "dusky yellow" is a darker shade of yellow but not gray-black. Am I correct and do the hens with gray-black shading disquality? Some of my best built hatchery pullets with dark colored shanks are also my best layers with reasonably nice body shapes so I'm thinking not to exclude them from breeding if they have other good qualities such as body shape and size. I don't know if the offspring will all have darker shanks or not but it'll be interesting to see. For now my breeding goals are production (egg laying) first with a secondary of breeding to standard. Some of the qualities I want exist in both production and the standard like body shape, size, capacity and condition, so I don't think I'm biting off more than I can chew in trying to breed for production and to the standards that also support production, if that makes sense. Like said, I'm just in the early learning/experimenting stages so I'm not looking to win any contests yet but I'd like to have a fair understanding of some of the standards such as shank color before I get started.

Thanks, Gene