I think that a hunting/fishing sub-forum would be very good to have here (after all, there is the meat birds section on BYC). My personal take, as a vegetarian, is if you can't stand the thought of Bambi swingin' from a tree, maybe you should stick to tofu and beans! Um, that's what we do. Those who don't want to check out that particular section can avoid it. Some people might not be comfortable with the idea of hunting, but I can't imagine any reasonable person interested in self-sufficiency would be offended at the idea of the section being available to those who are.
I also agree with a sewing/spinning/etc., sub-forum. For now I suppose it would fit in the homemade section, but I see so much interest in this over at BYC, I bet once this forum gets busy there will be enough interest here for that to take on a life (sub-forum!) of its own.
As for Livestock...I do really think that there could be separate forums for each individual type of animal. And for chickens, there could just be a link back to BYC. Oh, I forgot--Nifty has the backyard cows site up, too! I think it would be nice/easy to just have a sub-forum title for cattle and chickens and only have a link to those respective Backyard sites, no posts? The livestock sub-forum over there at BYC is great in that you can ask a question and there's sure to be someone there to answer it, but I bet a much more robust forum for Livestock would be popular over here.
I'm sure that there are going to be plenty of changes to the sub-forums as the site grows. I imagine Nifty hasn't set any of these sections in stone, and I bet it's just going to take opinions and a general feel of how the site is going to go once traffic picks up.