I have to many roosters and guinies running lose for a snake to go undetected they would sure let u know and I have railroad ties and the bottom of my pen. What else would be stealing them?
If you find shells with one end gone it is either skunks or rodents, no shell it is snakes, a partial shell it is usually the hens. Most snakes will hunt at night when it is cooler and they have darkness to their advantage.
Get some of that 1/2in bird netting from WalMart and just put it on the outside of the pens. A snake's head can go through it but not the body but they do get stuck in the netting. And think small. A rat can go through a hole the size of a quarter and a skunk can squeeze through an opening of just a few inches.
I think that Bill used a minnow trap with an egg placed inside and trapped quite a few new hat bands for himself a couple of years ago.