Train day: filler content.
These horses were watching the crucifixion in the Belvedere palace. They weren’t taking it very seriously. That’s understandable, because animals don’t have souls. It’s very sad for the wise and knowing looking donkeys and cows and sheep of the Nativity that they don’t have souls.* How awful, to watch the birth of the Messiah while knowing that you cease to exist at death. Why not be a satanist at that point. Take up with the goats.
Mediaeval artists really struggled to paint the faces of sheep.