I don't feed my girls lettuce, spinach, kale, or any other greens because they simply won't take them. Mine get all the greens in my yard, I took trips to parks and gathered other weeds or seeds from the weed stalks, and scattered them in my backyard. That was 5 months ago, and now I make sure my dad and I don't mow as often to let the grass/weeds grow. 5 minutes in my backyard and my girls are stuffed with all the grass they can get. I also bought a cheap bag of assorted bird seed and sprinkled it around my yard a couple months ago, it grew and they had a party with all of that, and some of the birdseed is still sprouting to this day.