You will lose some for sure but they are hardy animals with a will to live and they will adapt to the conditions.. You guys should try living where 36" of snow sucks but isn't out of the norm.. Last year I believe we had almost 2 1/2 months of more then 4 foot of snow on the ground and our winter lasted 3-4 months.. We lost some deer and this years crop wasn't the greatest but they pounce back in a hurry.. If it is possible to get some feed to your herd I would highly recommend it.. Just don't stop until you know they can veg for theirselves because they will be stuck without anything to eat... Most of our deer herd up and move to their normal winter grounds where they have plenty to eat and can survive.. So far this year we have had a weak winter so the deer are doing great and haven't had to leave the property (I'm sure an 80 acre standing cornfield isn't hurting things), we propared ourselves this year and left that field standing for the deer!!