One of the things I like to do when visitors mention sheep are stupid is to lean casually on a gate and, without even looking at the sheep, call them up, generally by saying "Lead them up to me 247" or something similar. The visitors don't know that they'd all come running anyway and 247 is always at the front because she's got the longest legs.
People who say sheep are stupid....hmm. A prey animal which makes itself scarce when its predator (us) approaches it in a suspicious way is a pretty smart sheep as far as I'm concerned. There may be some which will let themselves be loaded onto a float taking them for slaughter, but they probably have a dog at their backs. A sheep's behaviour is totally appropriate for its natural lifestyle - getting enough food, staying alive and reproducing. I think the stupid one just might be the human who expects a sheep to act like a human wants it to. The bright human will use the sheep's natural instincts to control it, like rattling a bucket of food, or putting a catching pen in the highest spot in the field.
It's the same with folk who say that a sheep just wants to find new ways to die. A sheep needs to hide any illness or damage from its predators right until it's so bad that it has to drop down dead. The skill for the human is to learn to recognise the small signs that something is wrong.
Sorry, not a lot to do with feeding over winter.