Okay.....I know this is an old post.....this just happened to me tonight. A week ago I found a black snake....5' long in my nesting box...I'm sure it got a couple of eggs down. I picked it up out of the box and put it near a shed where I definitely have mice. Didn't want to kill the snake. Tonight....got home a little late, went to the coop to secure the flock and noticed something weird about one of my chickens. It was dark so I couldn't see. I put my hand in and felt something strange. Had my husband run inside to grab a flashlight. Sure enough that same snake had one of my hens tied in a knot. I grabbed the snake and untwisted it....I got my hen freed. I had no idea a black snake would harm a full grown hen. Needless to say, as much as I hated to kill that snake....we killed it. My husband didn't want it left alive the first time.....it was definitely not going to be left alive after what we just witnessed.