My piggies always get a selection of 3 or 4 veggies at meal times, one of these is always a leaf veggie and it is nearly always lettuce. They also get a mix of other veggies like peppers, carrots, celery, spinach and parsley to name a few. Because these other veggies provide them with the vitamins they need is ok to also give them iceberg lettuce at the same time instead other types of lettuce they usually get? I wouldn't feed them iceberg all the time but sometimes the lettuce selection at the supermarket is limited.