I my neck of the U.P. it is very rare to see the abnormally small, fawn during the fall or abnormally small yearling deer, either bucks or does. If they are born late, they just don't survive. Also, most of the late born fawns are caused when fawns or yearling does are bred, which is also rare in my area (big woods, non-ag). In my area, on a good year, we only see about .5 fawns per doe in Nov. After hard winters, that ratio is worse. The small, weak ones just don't even make it to fall as they fall to predators since they are easier to catch than more well developed deer. It's easy to tell the difference between a fawn winter killed deer and older ones if you can see the skull, lower jaw, or even hoofs. Like I said before, I have only seen one winter in my area that killed a massive number of adult deer (1997). Other than that, the vast majority of winter killed deer remains that I have found were fawns even after years when yearling numbers may have been higher than fawns.