We've had success using mothballs (naphthalene) on our farm. There's a product called Snake-A-Way (also contains naphthalene) that's supposed to work but mothballs are cheaper.
Fantastic! I'll give the mothballs a go for sure.
So... Little dog, BIG GUN, little mothballs, BIG PANTS = snakeproof!
Come at me snakes!
I think your best best would be get some pants made with mothballs