Re: best way to protect livestock: I tend to build a wooden building without floors/ceiling. The door gets 'blocked' by a three-piece fence. Usually I build a slightly larger fence with a door around it as well. That way, I can enter the minor fenced enclosure with a new leashed animal, close the door behind me, deconstruct the fence directly in front of the building's door, open the door, unleash the animal when inside and get out without risking my other animals escaping all over the place. At most, they get a few steps outside the building where it's not too hard to chase them back in. Once everything is back in, close the door, reconstruct the fence in front of the door.
It's not entirely kill-proof, but limits possible kills by wild animals to those that can both open doors and climb over or destroy a fence. In other words, bears. Long as you keep a nice larger fence with bear traps or trap pits around your homestead, and another few traps surrounding the stable building (just be careful with traps and livestock when bringing new lifestock home. I've never tested it but wouldn't be surprised if a leashed animal is capable of stumbling into a trap if guided too close to it), the chances of a bear actually getting at your livestock is quite small.
As to what to do with surplus meat: trading. Dried/smoked meat will eventually spoil, even if kept in a cellar (though it takes a loooong time). I smoke during summer season and dry in winter, and generally make two* meat-selling trips a year: at the end of winter, I sell off all smoked meats I have left (which are anywhere from 6-12 months old by then), and at the end of summer, I sell off whatever dried meat is left (same).
*Two as in, I take the time to do so twice a year. Usually each "trip" consists of heading back and forth between my home and the closest settlement repeatedly. If there's a village entirely or almost entirely reachable over water, I may instead manage to take most of it with me at once by dumping it on the raft. (Due to limitations on how much you can take on a raft, both in weights and stacks, this works best if stuff stacks as much as possible. 2 bland smoked lynx cuts count as a stack. 471 tasty smoked elk cuts counts as one stack, too. For that reason, I tend to switch from eating oldest-first to from smallest-stack first during the latter half of a season, by which point I should pretty much be through most of the really old stuff anyway)
As for furs: look for foreign traders. At first, buy stuff you need/could use, especially stuff you either can't make yourself or won't easily find in settlements, including quality upgrades to stuff you already have. Once you pretty much have everything you *need*, look out for stuff that's easier to haul around to actual settlements/you can haul more of around at once. Valuables, arrows, anything reasonably valuable that weighs significantly less than the furs you're trading in for it. You can always look into grabbing a back-up weapon to have in case yours gets damaged, too--or extra tools to leave at places other than your home you nonetheless frequent a lot, to cut down on the number of items you have to haul around.
Make a nice stack of cords and bandages, too. You don't want your cuts to spoil because you didn't have enough cords around to smoke/dry it and had to make some first. Bandages never hurt to have. If you have multiple shelters around, especially in areas you take frequent hunting trips to, put a couple of bandages and some cords there too. Meats can't be smoked at a shelter, but they can be dried there. Dried cuts weigh a lot less than fresh ones, so in case of large or multiple kills, it's often easier to just leave them to dry there, put up a note when approx. they'll be done, and grab them at that time. (Consider felling a tree for the last stage of hideworking at such places too, especially if a fair while out from your main settlement, and dump either a stone on top or craft a club to leave there. The less you have to haul around on a daily basis, the better)
If you find you've got a couple of shelters you pay a lot of visits to, drop a few less-valuable larger furs there. Helps keeping you warm when sleeping, but also means you can immediately replace whatever cords or bandages you use rather than having to remember to replace them later. (Replacing the furs can simply be done by hanging around for a day or two to tan the kill's hide at the spot. You're not likely to be using masses of cords for anything other than preservation of fresh kills at such places anyway, so you should easily be able to replace what's used.)
If the shelter is near fish-able water, pick up a couple spare fishing rods in villages and leave them at such places. If there's absolutely no water near, not even puddles, consider putting a tub of water there. Again, the less to carry as standard item set, the better.
Always keep a couple of furs around the homestead to sleep on, to repair worn armor, craft more cords/bandages, etc.
Consider crafting a spare set of fur armor if you start going after more dangerous prey frequently, or if you deal with hostile humans a lot. Armor can degrade rather quickly in certain fights.