Lately my chickens are digging holes everywhere! They used to just scratch around under the bushes in their run, but now they have the whole perimeter of the fence dug around, and various holes everywhere, dirt covering everything! My daughter thinks they're looking for worms because it's been unseasonably rainy. Or maybe looking for dry dirt to dust bathe in? Are they trying to figure out where to lay eggs? (They're 20 weeks old and just starting to lay), or is it something else? It's just a lot of digging all the sudden, and this is our first flock of chickens so I'm curious. Thanks!