Never seen a 5' copperhead but have caught several in the 4' range and lots more 3' to 4'. We have a bunch in the woods behind the house. Not likely a copperhead will kill you but they may make you wish you were dead for awhile. Not really sure how they get along with chickens, chicken snakes and rat snakes are into the coop and barn but never had a copperhead or rattler in there (yet).
Ken
Ken