I don't have any ideas of how to build a chicken house or run that is snake proof. But I have built several of my brooding pens that are hopefully snake proof. I don't think the snakes will harm any of the adult chickens. The snakes are looking for an easier meal, like eggs, or an occasional mouse about the chicken pen. Now, they will eat the small baby chickens! The best thing to do is to prepare a brooding pen much like a rabbit cage. Use the small rabbit wire, or hardware cloth on it. Build it up on legs and use the small wire with the tiny squares. Snakes cannot get through this type wire. Be sure you have no cracks or holes anywhere. I was having a snake issue also. I built these type brooding pens and they are where I keep my mother hens when they have chicks. I eventually wean the chicks from the mothers and return the mothers to the run.
Snakes are crafty critters! They do not have to eat very often and they will gorge themselves when they do eat. I had a big black snack that probably lived on the farm behind me. When my hens would brood their eggs the snake was very smart to wait. He would wait until the eggs were almost ready to hatch and then come over and eat them literally right from under the hens. Very crafty devil. He knew which eggs to eat, and which to leave. Left the spoiled eggs. I was able to catch him and relocate him a long ways away! Scary as it was, I did it! Johnny
