If my characters have made camp in a wood for the night while travelling on horseback, what will the horses be doing?

I was sort of picturing them standing dozing together under a tree somewhere nearby -- possibly tied, possibly hobbled, possibly just being a herd together -- but poking around on the Internet suggests that if not shut up in a stable horses are actually quite active by night. (Which messes with the story, as quite apart from anything else nobody is going to be able to hear anything while keeping watch if the horses are busy foraging around!)