Yes you can tame Hebs Old Shep. They don't deserve the rep they sometimes get. If they are handled roughly then they are sensible enough to want to avoid humans, but treat them gently and they're soft as any.
TerryT - wethers shouldn't need much extra feeding at all. A handful of hard feed a day is too much between three - they'll get fat. Don't feed them ewe pencils or any ewe feed. A tiny sprinkle of tup coarse mix is plenty, every second day (psychological theory says intermittent reinforcement of desired behaviour, ie taming them, is more effective than rewarding them every time.)
The snow in zwartbles pic is thin enough (less than 20cm) that Hebs can easily scrape down through it to the grass below. They won't be getting much nutrition from winter grass, so a small amount of hay should be plenty. If they demolish what you give them in seconds flat, then they are hungry and need more. Hebs are never greedy - they know what they need and take only that much (unless it's hard feed in which case they can't judge so easily). Don't forget that they love some leaves or branches in winter for vits and minerals. Willow, apple and so on is fine, but not evergreens or things they don't rush for.