I haven't ever considered allowing a snake to stay. I'll usually relocate them. That said, a rat snake wrapped itself around a post on the front porch last week at a high rate of speed after I caught it in the aviary with a cockatiel inside it. The aviary was snake proof until the chickens dug a dust bathing hole on one side of the aviary wall, while the small group of quail that maintain the aviary, dug holes for laying eggs against the wall from the other side, leaving a small hole, just large enough for a snake to get through to make a meal of my cockatiels. Snakes don't bother me around the chickens, as I won't miss an egg it two and they'll never be able to eat the chickens, but I draw the line at my tiels.
