Opening weekend-Sunday afternoon I saw some guys in Mills county that had 3 deer on a 16' utility trailer. Deer had been hanging overnight; they were on the trailer for a while and they were adding bags of ice to the cavity. The meat isn't in the cavity. No telling how far they were going. I would not want to eat at their house.

Me either.

I've never let one go overnight - as said earlier, on my place the coyotes would have it cleaned by morning. Plus, what I have always practiced, is to get the guts and blood out as soon as possible, because just that heat alone can cause the meat to start to taint. Not sure if luck, good shooting, or a combination of both, but I've never failed to find a deer that I have shot, usually within a hundred yards or so of shot. And getting off topic, the other key is patience. Unless I can see where the deer falls and sure it is dead, I just sit, at least 20-30 minutes, and then may go get the Mule and come back. Unless just a really bad shot, they will likely die fairly close if not pushed early.

Hanging a field dressed deer overnight is a completely different matter.

I have a dog that will find a wounded deer. He has found several deer for people that were left over night. Some were just fine. Others were partially consumed by either coyotes or hogs. On a gut shot deer it’s best to leave it 4-6 hours. If gut shot just before dark, leaving it overnight increases your odds of recovery. Unless it’s hot outside the meat will be fine.
I’ve watched several hunting shows where I’ve made the assumption the only reason an animal was left overnight was to have better light for filming the next day.

i'd think it would really need to be pretty cold. We've on occasion gone back to look again in the morning for a deer/hog that we did not find the night before. With deer at least its never been the case that we found one the following day, the animal wasn't dead. Some big hogs shot in the dark that we knew we weren't going to eat we left til the next day just so we could look in the daylight. It would certainly be my preference to not ever leave an animal once shot. I also believe in giving them a little time after the shot...but i'd think any reasonably shot animal will be dead within a few minutes or maybe 15-20 at the most. If they're surviving longer than that then they really weren't hit well and odds of recovery within the 24hr period probably aren't good. I agree with what was said above about the tv shows always leaving them overnight....the point of the show is not meat retention. i saw a show once where a guy shot a deer late and didn't even try to look for it. he said on the show that he had to leave to catch a plane to another hunt location...that if the deer was found they'd mail it to him. pretty disgusting.

for me...even if a deer is dead in front of me...i try to give it 10-15min before i get out of the stand and approach it. if the deer ran out of sight i'll still give it 10-15min and the i'll go look at the point of impact for sign. if i'm seeing good sign i'll follow up and look until i find or until it seems likely that the animal is not dead and i'm not going to find. leaving an animal overnight purposefully seems un-necessary.

once a deer is recovered and gutted, if its at least 50-ish deg, we commonly will let them hang overnight to chill out and skin later....or at least until we've got some breakfast and coffee.