Nope, not kill the ugly. I love mice and rats as pets, too.
And dogs don't even compare enough to enter this discussion. Dogs are people! They just happen to wear fur. Actually, I shouldn't say that dogs are people. That would be insulting dogs.
"He is your friend, your partner, your defender, your dog. You are his life, his love, his leader.
He will be yours, faithful and true to the last beat of his heart. You owe it to him to be worthy of such devotion."-Unknown