Snakes came into my house via some holes in my soffit/facia (sp?). And right on up into my attic. Once the attic got too hot, they would find their way into the house, and then find me! We've since made the house as air tight and sealed as possible and haven't seen a snake since July (knock on wood!).
My house HAS to smell like humans, not to mention that I have 2 cats and 2 dogs...
I highly doubt the hair would work. Neither does mothballs, snake away, or sticky traps. They may deter for a while, but where there's one snake, there's bound to be more.
Just use expanding foam and hardware cloth on every crack and crevice that you find. Gather the eggs early if possible, not leaving a free meal out in the coop for long. And keep the yard free of debris that a snake could hide under or around. These things really worked for me.
Garter snakes were killed and consumed by my chickens twice now, and I did nothing to intervene... I figured if they attacked and killed them it was one less for me to worry about.
Good Luck!