A dog, especially a german shepherd (& other traditional guard dogs), is only doing its job. However, No dog should be left outside to fend for itself. Dogs are pack animals. They want to be with their people. But poisoning an animal because its owner doesn't understand this principle is diabolical. There are other courses to take. My GS is an inside boy. But if he were left out one day, having him poisoned would feel like murder to me. He is a beloved member of our family. No one has that right. And if the outside dog has hurt or even threatened someone, then call the police.