Our barn is a bit a distance from our house and we had one injured horse so during some bad weather we left a couple of lights on.
However, when looking out to check on the horse......the horses were staying as far away from the barn as possible in the pen. Only a couple of times did the horses go in the barn after dark....even though it was warmer there.
Of course if I turn the light I couldn't tell if they were in the barn or not but I am thinking they don't care for the light at night.
Just curious of what others have experienced.