my buddies and i have researched this topic quit a bit. my family has always hung their deer for 4-5 days in 40d weather.last year my buddie and i left the hide on! and let hang for a week! i know i know.it was by far the best meat iv had on both of the deer.the meat didnt have the tough outer layer on it it came off with the hide. we had thermometers in them and the meat was 39d. im doing the same thing come thursday when muzzleloader season opens.