Place the drained sauerkraut in the insert of a 4-quart slow cooker. Add the onion, carrot, garlic, caraway seeds, thyme, bay leaves, juniper berries or gin, and black pepper. Combine them thoroughly with a fork or with your hands. Scatter the kielbasa on top and bury the hocks in the sauerkraut. Pour in the wine and broth. Cover and cook on LOW for 9 hours, until the juices are bubbling and the sauerkraut has lost its crunch.
Remove the smoked hocks. If there is any meat on them, remove it and add it to the sauerkraut. Discard the bay leaves. Serve the braised sauerkraut as is with boiled potatoes, or use as a base for choucroute garni.