We don't have any poisonous snakes here, but I understand your fear. This is the year of the snake for me. Last summer, there were a few (well, maybe more than a few!) garter snakes living among the leaf bags in the sheet compost area. Yesterday, the dog was having a hissy fit about one she found. A few minutes later, the chickens were having a business meeting about what to do with the huge garter snake that was slithering around in their run. I've also seen 2 smaller snakes so far this season. I like my snakes, as long as I don't get surprised and almost step on one.
As for missing eggs, any predator could be to blame. Game camera would be a good idea.
As for missing eggs, any predator could be to blame. Game camera would be a good idea.