During the spring, our guineas went through a period where they kept waking up and making a lot of noise at night. I would go out and look but couldn’t find anything. A game camera showed the basic wildlife we have, including deer that likes to walk by there at night. I think that the guineas were just a bit freaked out by the season change and changes in our normal night time noises. After about a month they calmed back down and just occasionally alert at night. I also put a night light out for them, mostly in case another snake gets in the coop, but I think it might also help them feel more secure when they hear noise.