@SerenaT Not only vitamin D, sunlight has many more beneficial properties, for example it triggers synthesis and release of nitric oxide from the skin into the blood; nitric oxide dilates blood vessels, decreases blood pressure, improves circulation and in general reduces the risk of cardiovascular diseases.
pets.stackexchange.com/questions/31347/… I had no idea that "chicken tractors" were actually a retail thing. We had something like that for our poultry when we raised it, but it was all home-designed and built. I learned something today!