We have bears here, and I see bears on the property yearly (on the game cams, usually not in person) and those bears are generally moving about in the wee hours of very early morning.
Because of that, I have horses in overnight and out during the day. I don’t really worry about the bears going after the horses–although a bear did kill a little donkey a few years ago just a few towns over–but I do really worry about the horses freaking out enough about a bear to run through the fence. And horses going through a fence at 4 am would really, really suck. So, they stay in.
If we didn’t have bears, they’d totally be out overnight!