It' s up to the individual hunter to decide what is ethical for him or herself. If you are just hunting to manage the wildlife in your area then there isn' t much wrong with leaving it there. I don' t suppose your going to eat it anyway, might as well let something else do it for you.

But I always skin mine unless it' s a coyote in the summer when thier coat is all screwed up and smelly. I always take pictures too. Then I save the skull. After that, I leave the body in the woods for the possums.

(Except bobcats which are mighty tastey).

I love tanning hides and making stuff with them. So if I were you I would at least save the hides in case one day you wanted to have them tanned.