But the LGDs of antiquity caught their prey. They were often out there with no supervision for weeks, and nobody provided anything for them. And a sheep does not die every day or even every week. This led to dogs with low metabolisms.
I know my dogs have eaten things they killed and lived off it for a few days. Sometimes, they just won't eat their food, but I can tell they ate something (I am a vet, after all). When we killed chickens this fall, I fed the dogs for a week off the innards and feet, until I got tired of stinky guts and threw them away. I'm not too fussed about how I'd feed my dogs, as I have space and land to raise a lot of different critters to provide for my family (I already do this) and a large garden. I'd be more concerned if I had a high energy dog that could not help provide its own food.