As noted in another thread, I have a white mulberry planted inside my chicken yard. My thought is to provide the hens with some fresh fruit without dealing with the staining issue of the darker berries. Even though my little whip is only about 3' tall, it gave me one berry last year. It was a bit difficult to find a white mulberry, I ended up ordering online from a nursery down in Oregon - none of my local nurseries carried it.
