Vegetables Various types of lettuce enough variety?

Besides the bell pepper my girls get every day, they have seemingly decided that only the leafiest of vegetables are worth their eating effort. I usually at least try to add more to their vegetables, but it's kind of disheartening to watch them sit there, stuff their little mouths and then see a battlefield of fallen carrots, celery, tomatoes, etc. when they wander off for naps. Mostly because I like tomatoes, celery, peas, carrots, whatever and I would really rather eat them myself if they're not going to.

They get, usually, red/green leaf lettuce, little gem lettuce, radicchio, belgian endive, a mixture of baby lettuce (romaine/leaf/oak/butter mix) every day. Cilantro most days. Additionally I'll also give a couple of times a week one of the following: spinach, kale, dandelion greens and (a very distant maybe) broccoli.