We made a couple of planters with screen covers so there are constantly growing greens for the chickens. They can chomp down to the wire, but they can't scratch or dig in the planter so the greens keep growing. This first time I just thew in handfuls of birdseed to see what would happen...everything grew and the chickens love it all, but some of it is thick leaved and can't make it through the mesh. Also, some of it is one time only...chickies eat the tops and the plant is history, unlike grass which keeps growing. So my question is, am I limited to grass to keep these boxes constantly growing? Are there any grains that continue to grow like grass? Is grass alone useful enough? I don't mind reseeding...but it would be handy if I didn't have to. Thoughts? Suggestions?