Fencing overall is a fairly cheap way to protect your animals. Don't get lured into a false economy of cheaper alternatives. Cheapest is rarely the least expensive.
Good fencing will not only keep your horses on your property, it will keep other people's animals off, and will prevent injury to your animal. Inappropriate fencing can lead to direct injury to your animals (e.g. hoof getting caught), or indirect injury (e.g. allowing predators in, or not effectively containing your animal thereby exposing them to being hit by vehicles, shot by neighbors, accessing hazardous terrain, etc).
I've not tried to run my
chickens with hooved animals, so no idea if that would work OK or not. If your fencing will contain
chickens along with the horses you can give a go, but be prepared to separate them if the horses either purposely or accidentally start killing the chickens.