Thanks for the article. I had already known and followed a lot of this info, but it is always good to read to see if you can come up with additional info/ideas. And I'm happy to say that you've triggered one very good idea to improve my setup. I have 3 girls and one of the problems I've had to deal with is where they've been doing most of their dust-bathing: In the soft soil around a new fruit tree, exposing and damaging some of the roots.
I'm going to put in a small fence to protect that tree, but that doesn't eliminate the need/desire for an open dust-bath area. Instead, I'm going to put a tire under an established tree for dust-bathing. That should keep them from destroying another area and also provide good cover.
FYI- I agree that fewer birds are a positive when it makes sense. My three are in a chicken tractor that I move every two days for 9 months and park for 3 months. For most of the year, they can forage while in the tractor, pooping and partly eating the plants. I found that moving them every two days means that they don't kill the plants and the area grows back and is at least as healthy as the surrounding area after 2-3 weeks (depending mostly on precipitation). In the winter, they get to compost my leaves. This helps me, but also gives them something more interesting to play around in during the cold/dreary days than bare dirt.