Both of them are Blue heelers, I use them to help with cattle and they listen wonderfully! They have never ever killed a chicken when I was around, just when they were loose and I was inside for about and hour or so. They have no way of getting bored on our very large from, so being bored couldn't possibly be it. My chickens don't have a run or any way of keeping them confined, my other two dogs both labs do a wonderful job at keeping predictors away from my chickens both at night and during the day. My two heelers have currently been moved away from where the chickens walk around, I was hoping if they were tied kinda close to the chickens they would learn to be around them and not harm them. That did work for about a month, til a chicken wondered over to the dog and must have been taken by surprise. I am going to try a muzzle for when the dogs are loose and I am not around to watch them, this will not harm them in any way and both chickens and dogs will be safe. Then perhaps after awhile they will learn not to bother with the chickens cause it is no longer enjoyable anymore.