... what did the guy's vehicle look like afterward? Sheep are big creatures. I would think sheep in the road would be killing cars and drivers also??? Not using salt seems like a no-brainer. If I saw a sign about bighorn sheep being in the road I would be more worried about ME than the sheep.
They didn't say what type of truck is was but suppose it was a semi and trailer. They can weigh upwards of 80,000 lbs and don't stop on a dime and looking at the picture it looks like it may of been snowing or had just stopped. Even if it was a pickup it would take quite a while to stop on bad roads. Their problem now is probably going to be solved by a 8' high fence to keep the sheep off of the roadway. The state highway department here in Colorado has done just that. Now all the DOW needs to do is figure out how to let the animals migrate to and from their winter grounds instead of keeping them fenced in.
If you're lucky enough to be on private land and can leave your stand up during the off season you can tie an old piece of cloth or something of the sort to your stand. I like to use an old camo bandana that I have. That way the deer get used to the movement and eventually don't bother even looking up when there is slight movement. This may just give you the time to draw your bow or raise your gun without being detected.