I think its depends on the animal,,
but an ethical distance would be the distance you are accurate under pressure,, not the target range when warmed up,,
or shooting groups,,
so I think start closer than you think and if your success rate is good,, then extend your ethical range a little at a time if needed,,
deer do move alot sometimes,,taking that into consideration,, i dont like to shoot further than 15 yards,,
if someone told me,, Brad, I killed every deer I shot at 25 yards,, then I would say you are shooting an ethical distance,, everyone is different,,
if the deer would stand still and you hit him at 100 yards your bow would be deadly, so its not a matter of how effective your bow is,, just a matter of being able to get the arrow in the right spot with all the variables,,, the closer you are the better your chance of success,,