Always gave out dogs liver (Boxers). We were told to be careful of offal and keep it to one or two times a week. An Ox heart is good for them and they love it. As stated above dogs are designed to eat raw meat.
Another little trick was to pour blood over the biscuits - they love it.
I agree that dogs are meant to eat raw. But it still needs to be balanced for nutrients. The reason I said to start small is that if a dog is not used to it, it can cause issues at first. That was my experience even with small amounts.
actually they aren't. The ancestors of our domestic dogs was a midden scavenger so yes there will have been some raw meat but mostly it will have been rubbish from the villagers food including grain, cooked food and "human manure"