To quote Indiana Jones...

[Sardou]

"Snakes... I hate snakes." I lost four biddies to a big chicken snake last month. I had two brown leghorns and two barn rocks about 10 weeks old. They were kept overnight in a cage in our garage while my husband finished the chicken tractor and a chicken snake got into the cage and ate all four! When I opened the garage in the morning, the snake was sleeping off his meal inside the cage. There were no chickens left. Needless to say, it was traumatizing, and before I acquire any more chicks I want top make sure I've done everything possible to keep them from snakes and other predators.
I've just read all the posts here and it seems that sulfur is most effective. I'm also considering those electronic pest repellers and hiring a Brinks security guard.
By the way, I contemplated what to do with the snake all day after it happened. It couldn't get out of the cage because of course it was too fat to get through the mesh with its huge meal. I am sorry I am was not able to accept the snake for being a snake, and doing what came naturally, but the snake was dispatched by my husband as soon as he got home from work. Does that make me a bad person? I was not able to do anything else. I loved my chickens. They were eating feed from my hands and roosting on my arm before this happened. They were my delight.
Despite this heartbreak, I would like to try again, but maybe with the help of this forum I can be a better Chicken MOM.

 

[kinnip]

In my experience, animals are habit formers. If that snake knew where to get a yummy chicken dinner, he'd be back for more. Also, I'd be pretty p.o.ed too. So far, I haven't had to kill a snake, most of them are too small to eat a chicken. If that happened to me, the snake would be toast.

 

[jenjscott]

Sulfur is good, just remember to re apply after a rain. Using 1/2 inch hardware cloth is good. Use it to cover any and all openings. If the tractor will be the complete housing for the chickens it will be easier to snake-proof than if you have a large run. Chickens are so much fun. But predators are always a possibility. Try it again!