Half inch hardware cloth works well, just a fence won't really keep out snakes you have to have a roof too. Those suckers can climb, I've seen em go straight up a tree or wall. I have a three strike rule, once in the house eating eggs, relocate across the road. Twice, take to the end of the road. Three times and they die. Unless they kill a chick, then they die the first time. They come and kill 8-9 week old ones and and leave the body cause its too big, even a seven ft long black snake still can't swallow a 8 weekold. Bird netting catches other things than snakes, which can be a problem because then that attracts other predators.