Terrible things happened to two of Mom’s friends and their animals last week. Neighborhood dogs killed her friend Lauren’s sweet mama goat while Lauren and her husband were away. Then a neighbor’s dog attacked her friend Becca’s pregnant, much loved ewes. One ewe was killed, the other was so horribly mutilated that Becca’s husband had to put her down.

Dog attacks like these are not isolated incidents. Hardly a month goes by that someone on one of Mom’s sheep and goat listserv groups doesn’t report injuries or deaths caused by dog attacks. The National Agricultural Statistics Service says that 22.7 percent of the 247,200 sheep killed in 2009 were by dogs.

Livestock can be in trouble when dog owners think their household pets or farm dogs would never kill livestock and they let them run wild instead of keeping them at home. However, dogs of all breeds, sizes and temperaments are potential predators. Predatory dog behavior, as the experts call it, is hard-wired into what makes a dog a dog. Under the right circumstances, most dogs will chase and kill livestock, unless it’s a dog trained to guard livestock.

We have seven dogs on our farm and the only ones Mom and Dad trust unsupervised around us goats and sheep are our livestock guardian dog, Feyza; Feyza’s new apprentice, Nuray (she’s a livestock guardian puppy); and our farm dog, Steve. The rest can only interact with us when Mom or Dad is around to watch. A strong woven-wire fence and Feyza keep our neighbors’ dogs off of our farm.

Do you think your dog would never kill a sheep, goat, alpaca or foal? You could be wrong. Researchers in Australia studied 1,400 dogs that attacked livestock and learned most livestock killers were family pets that got plenty of food at home. Specially trained tracking dogs followed the trail of the predator dogs back to their homes and caught a mixture of dogs from 3 months to 12 years old, purebreds and mixed breeds, and intact and spayed or neutered. Even the dogs bred to not harm other animals couldn’t resist the urge attack livestock, so it’s impossible to predict whether your dog will attack livestock.

Dog owners often think that only packs of dogs attack livestock, but this isn’t so. In the Australian study, 40 percent of attacks were by single dogs, 51 percent involved two dogs, and only 9 percent were by three or more dogs.

Dogs attack all types of livestock and poultry—sometimes even llamas and donkeys kept for guarding sheep and goats. Sheep, goats and poultry, however, bear the brunt of dog predation. These animals flee wildly when dogs attack, and this is the type of action that feeds predatory behavior.

Dogs chase prey for fun. Instead of killing and eating a single sheep, for instance, they pursue the entire flock at top speed, ripping off ears and faces, peeling off huge strips of hide, and generally mutilating but not outright killing their prey. Most sheep die later from injuries or exhaustion; chased ewes often abort their lambs.

The solution? Never allow your dogs to roam at large—keep them at home on your farm. It’s also worth noting that dog owners are responsible for damages when their dogs kill or injure livestock, and in most states, farmers are legally empowered to shoot any dog harassing their stock.

If you’re considering adding livestock to your farm, remember: You must protect your new livestock from your own dogs, too. You never want to experience the aftermath of a dog attack, especially when your own dogs are involved. Securely fence dogs away from livestock areas and only allow your dogs among the stock when you’re around. And consider adding a livestock guardian animal to your farm. Unsupervised dogs and livestock don’t mix.