I had this same issue the summer before this last. With the drought the midwest and south has been having (surprisingly this year so far not so much), the rabbits, squirrels, field mice ect..., go searching for different food since the corn and other crops were dried-up.
Anyway, we live next to an old farmer who's lived out here his entire life so being that he's only 200acres away we figured he'd be having the same issue so we went to check on him and ensure he was ok between the heat & snakes. He was fine and was having absolutely no snake issue which dumbfounded us. Then he let us in on his "secret".
Here's what works for him and what we do now because it does work!
Go to a local barbershop and pick up the scrap hair that they cut for a couple days or weeks depending on the amount of traffic at the barber. Spread it around the parameter of the property. The human hair has a ton of scent which keep the critterthat the snakes hunt away and in turn durastically cuts down on the snakes (this also works for if you have an issue with deer eating crop seed). I explain the reaction as being like a forcefield lol.
This is what works for us & we have not only copperheads but cottonmouths along with coyotes, feral hogs & even the occasional bear in the area but haven't had an issue with any of the above since using this method.
Hope you get your issue taken care of. Copperheads are aggressive & getting bit is no fun. Let me tell you.