What about getting a pig? lol They'll kill snakes and they're magical because they turn stuff into bacon.
There is a product called Snake Mole Grub, SMG, that is Texas red cedar oil. Works great for keeping snakes, moles, and grubs out of any area.
This is the source, mfg. http://www.cedarcidestore.com/cedarproducts.html We sell it at growfresh in season. I bought a gallon a few years back and I really like it, so much that I sell it now, I have the PCO because the 'best yet' was not yet available. I think the PCO or SMG are what you are after. It seems pricey but it will last years. My wife uses it on her horses, we use it on our dogs, and their bedding, around the house, as bug spray... The list goes on. I use it alternately with ECO Exempt IC2 (which is under a different name now...?) for bug control in the summer.
Dave Durkin said:
@Paul: Thank you. I'll look into it.