My wife has this theory that if a snake is big enough to see, it's big enough to run from... and if she has to run from it, I have to kill it.
Nothing makes her scream like spotting a snake or a mouse.
When I was a kid, we had a wooden egg to put in the nest to encourage the hens to lay there, not where ever they felt like it. Never had snake issues, but raccoons and possums liked eggs... and hens.
Good luck finding your current issue.