This is a very nice blue roan that is wearing a halter. I haven't seen him before. Did BLM release him and leave the halter on? Did someone try to capture him and lost the horse and the halter? Is he privately owned and got away from the owner? Don't know. Maybe the halter is designed to fall away by using Velcro closures. I rattled off about 6 images as he ran by. From years of hunting I instinctively lead running animals and tend to crop them with cameras. This guy was a beautiful animal. Hope I see him again.