No, they’re not ugly. But, the entire flock is running away and making the Shepherd chase it. They shouldn’t be able to get through the gate without someone opening them for it (unless they’re smarter than the Hearthlings).
It might have something to do with the fact that the Shepherd forgets to feed them! To the point where they start taking starvation damage. I’ve got enough in-game things to worry about without having to keep an eye on the flock health.
I’ve had this happen in two Ascendancy games. In one of those two cases, the sheep feed bag was sitting right in the middle of the sheep pen, unopened, and then simply left there. In another situation, the sheep bag was opened right next to the container that it had been stored in - which drew the sheep to the middle of my town from the outskirts. Which made the Shepherd have to lead them all back to their sheep pen.
I don’t know if the Shepherd was smoking some of the local flora and simply forgot or what. But the little jerk never went back to feed them in either game. He’ll butcher them just fine. Feed them? Nah, he’s got stuff to do like schmooze up the lady blacksmith.
These incidents were in back-to-back games and this has never happened to me before.