I guess to really answer this question I would have to fully explore the definition of the word "ethics"... which it is to late at night to do, so instead I will ramble & muse about the current discussion
who/what deserves to be treated ethically? Do people deserve better/more ethical treatment than animals? Do cows deserve better treatment than ants? etc...
I would ask, what about the plants? they are living. Even, what about the mountains, the granite, the rocks, the clouds, the rain, the swell of the tides? Should the animate, the growing, get better treatmen than inanimate? hmmm. I would like to teach my son respect for all life. For the earth, for the world, for all the elements that create us.
Does the ethical treatment of all things/all of us (people, animals, plants, earth, you name it) reside in balance, in awareness? Is it ethical for me to eat sausage? If I do so without contributing to cesspools of pig shit, maybe. Is it ethical for me to bake bread? If I can do so without contributing to genetically altered wheat production, maybe. Is it ethical for me to take my DS to the zoo & see the animals that were stolen from their homes for our amusement? if... and so on...
I believe: each action I take ripples outward from me, to you. Is that principle the beginning of understanding what is ethical?