We don't seem to have any losses to snakes out in the duck pen, I do have a couple ducks who insist on setting in the barn and my rat snakes occasionally will feast on their eggs. Usually you hear a duck really distressed and if you look, there will be a rat snake in her nest or nearby. They don't seem to take very many and I love them there for the mice and rats, so I call it a fair trade. And our guys are close to six feet.
Porkpal, one of the main uses for ceramic eggs is snake control here. They break inside the snake and the sharp edges kill the snake.
Our rat snakes can be grumpy, especially when you relocate them, this one was under a stump in our side yard. Evan put him in the barn.