Bobby is correct. a few 'T' posts and some 4 strands of barbed wire will keep out the cows. space the wire wide enough that deer can go through the wire but cows cant. they will also jump it. added benefits are that the only tracks under the feeder will be the deer and, if you shoot a deer the fence helps (but not necessarily prevents) to keep deer from running after they are shot. They can still jump after they are shot but it will slow them down a bit. Figure an areaat least 10 or so feet out from the feeder and you wantthe area big enough so that the corn throw by the feeder stays in the fence. Be sure to leave yourself a gate wide enough to drive a truck into so you can fill your feeder. good luck.