Okay, I redid my snakes' enclosure. I put a layer of ground clay kitty litter in the bottom, mixed with the baked mulch I had in there previously. I also put in a large shallow plastic pan of water.

And get this: yesterday, I put a few minnows from the bait shop in the water, just to see how the snakes would react. And just a moment ago, I caught the green one "gone fishin'!" I would have got a pic, but I didn't want to disturb her dinner - this is the first evidence I've seen that she's eaten anything I've put in there so far! I'm sure she ate at least one (I could see the bulge in her belly after swallowing it), and she looked to be going back for seconds. Again, I really didn't want to disturb her since this is the first time I've seen any evidence of her eating at all.