I would never kill another human because they are literally one of our kind!
What's the point of killing humans if you're only going to use their heads as trophies? The rest of the body is going to go unused. Human meat also tastes terrible and sour, and your body won't be able to digest it because evolution affects your body; the majority of humans in the past have most likely never eaten human meat and/or adapted to it. Some people might also have contagious parasites or some sort of illness inside them that will kill you if you consume their meat, as well.
Feeding the rest of the body to your dogs also raise a risk. Some sailors may have eaten foods (such as fish) that are poisonous for dogs, and it could kill them.
Imagine the pain and suffering others with intelligence will have to go through because of you!