I've orphaned my share of fawns over the years and choose not to do it anymore. The fawn may be weened and can eat regular food, but it really needs the doe to teach it how to survive, ie find new food sources, make it thru the winter, evade predatorsand watch out for the boogy man hiding in the trees. If I need to shoot something, I'll take the fawn.
Altho we tend to use the terms fawn and yearling interchangeably, they are not the same. A deer is not a yearling until it is a full year old. Button bucks and the small does will have lost their spots with the change of coats, but they are still fawns. The yearling doe, now about 1 1/2 years old and likely without a fawn, is high on my "hit list".