I don't know about the shanks? Could be the pic or could be that this guy is just looking goofy at the moment. In general I think he's just going through a really awful teen stage right now. LOL!
My pure Swede roo took FOREVER to fill out. Now at over one year old, he looks huge and incredible, but it took a lot of patience to get there! I don't think he started to look mature until he was 9 or 10 months old. While I hate the fading white from the Buff Rock, I do love how early those Rocks would fill out compared to the Swedes!
Oh, funny thing, the one really "unique" roo here who is orangey-buff with tons of white mottling and little/no black, who looks like ????? no other breed at all, is leaning towards the "early maturing" type . . . he's already jumping on the young hens and "breeding" them. (For all the good it does, considering they aren't laying yet.)
He's also doing some lousy squeaky crowing every day. It sounds terrible, but considering I need him to step in and cover some hens as soon as possible (since he's the most exciting colored roo I've had in ages) the "creaky hinge" noises he's making are music to my ears! LOL!
He is also not looking as "rangy" as the more Swedish-looking rooster, and is overall very attractive and stout even now, although to be fair, he probably won't be quite as large as the lanky guy shown above.