I think the leg color is photo quality rather than anything "odd" for a BR. That's a single barring gene Cockeral, you get single barring in an outcross to a non-barred breed, so yes could be sexlink, or anything else they decide to outcross to so they could more easily feather sex the line. That's the problem with hatchery stock, they'll do whatever works for production and purity be darned. Bred to barred birds he'll continue to produce barred, bred to non-barred birds, he'll produce barred males and non-barred females. So he works for the hatcheries goals, but not as well for the home flock when you'd like an actual BARRED ROCK.