A Villager's Scarecrow:Is there any device to scare crow,wild animals like elephant etc; to save the crop?

We live on a farm in Wisconsin and when our dog died we were left with an old dog that could not chase away coyotes and deer from our chickens and corn fields so what my dad did was put out speakers with timers on them so that at night there would be a constant sound of a dog barking. It worked really well and we took it down after two weeks and we have had significantly less problems with wild animals so your radio idea is a good one but try having a stream of a lion roar or something more threatening to elephants than human sounds.