I`ve shot many deer in spine,all have been right below me.I hunt thick most of the time.Every one of them drop were they stand.some twitch some did not.I beleve when when you shoot a deer with a razzor sharp broad head it does not feal a thing.[exsample] shot a doe once,ran about 10yrds and keap on eating.Did not feel a thing. bullets burn- razzor blades do not.that twitching is the nerves.they hemrage so fast they dont feel a thing.Plus I`m there to put meat on the table and a trofhey on the wall.I`ll take a spine shot or a double-lung,they both do the job.
The most humane way to kill a deer is with bow and arrow.