My 3 redfoot torts each have something they seek out and try to eat when I bring them outside. Filia goes for rocks, Amelia bites trees like see trying to eat the bark, and Lina goes for twigs and sticks. They do this even with a giant pile of food for each of them. How do I get them to stop, it's kind of difficult watching 3 of them to make sure no one is eating twigs and rocks, and I don't have time to bring them each out individually.