I've looked at many a post here about barking or invading dogs. I've had a device for quite some time called the "Dazer". My stepfather was issued one of these when he worked for the phone company many years ago to scare dogs off when coming down off a telephone pole. I found them on the internet and ordered one for myself. I think at the time it was about $40 but a quick google and there are many similar devices available for much cheaper. It looks like a garage door remote and has a single button on it. When you press the button it emits an extremely high pitched and apparently to dogs, quite loud and painful sound. Most people can't even hear it and those that can have to have the device quite close to their ears to hear it. I can hear it within about a foot of my ear and it's clear why dogs don't like it. The sound it makes seems to invade deep into your bones! It's hard to describe a "painful" sound but that's exactly what it is. I have nothing to do with the sale of these things so this is NOT an add. I've just had great success with it and it seems many others are in despair about what to do with barking or invading dogs and maybe this can help. I had a dog next door that would bark constantly any time we were out back......until I "deployed" the dazer. He would bark, I would go over and "daze" him and he would immediately stop barking, turn to and march the other direction. It took about 2 weeks of "treatment" to solve the problem. He no longer barks when we are out and very rarely does he bark at all. My wife pointed out our own dogs one day while I was 'treating" the dog next door. Our dogs were also heading the other way even though this thing seems quite directional, they could clearly hear it and didn't like it. I also used it one day to stop a dog in its tracks while on a walk with a young puppy. A large dog came out of blue running toward me barking and baring its teeth. I don't know if it was me or the puppy he wanted but he meant business. Fortunately I had the dazer in my pocket so I pulled it out and "dazed" the dog. He stopped like he hit a wall, turned around and walked slowly away. I see on various sites that they make much more powerful, non-portable units as well. I guess you could mount one on the coop and have a button to press or maybe a motion switch or if you don't have any dogs I guess it could just be on all the time. I can tell you that these things work and work extremely well and any human around doesn't have the foggiest idea anything is going on as they can't hear the thing. This thing has worked like magic with my dog issues and I'm sure anyone here with dog, wolf, coyote or any other canid issue would definately benifit from these devices. It works on some cats too. Some seem to not hear it at all and others scatter. I have no idea about skunks or racoons or other predators but it sure as heck works on dogs. This was the site on the top of the google list when I searched for "sonic dog repeller" but there's a ton of sites out there that seem to sell similar devices. http://www.ultimatebarkcontrol.com/ Good luck to anyone with dog issues. There's nothing worse then a dog next door that won't shut up! Except, I suppose, a dog next door that won't shut up AND eats your chickens!