If they can even get up they can't go more than 5 feet without dropping again because they can't breathe.
They breath through the trachea (wind pipe). The esophagus is the tube they swallow food through.
Even the wind pipe is not an anchoring shot. A deer can run 100 yards with a blown out heart and no oxygen enriched blood going to the brain. I can assure you they'll go pretty far not being able to breath.
I shot in the neck will usually take out the spine and can also sever the carotid artery and jugular vein. These are probably what is causing your deer to drop.
You guys aren't vascular surgeons, are you?
