I have to say, since Jim made our homemade "night eyes" we have had NO signs of any predators around the coop or run. He used a piece of PVC pipe & put six red "eyes" around it & I don't know what all to wire it with- it runs off of two AA batteries. I flip the switch on it when I shut them up at night & it blinks rapidly & you can see it from a long way off.
I used to hear the roo sound an alarm call in the wee hours before sunrise but not anymore. No tracks, no signs of anything digging or pushing on the wire or anything, no noises from the peas either, who are right next door. So apparently, it works. I saw an ad for one that runs off a solar cell so that will be Jim's next project so we don't have to use battery power.