Lots of grasses grow well in shade. There is enough light from scattered sunlight or from holes.
There are lots of plants that grow in shade. I have a corner of my yard that receives almost no direct sunlight, but native plants from forest do well.
That’s true but it’s never the highly nutritious grasses that cows/goats need like alfalfa, false plantains, millets etc. You would need to heavily supplement their diets, I would imagine.
The panels were spaced out enough that light was hitting part of the grass, and would probably hit all or most of it throughout the day