This is interesting. I have been watching a programme called "The Secret Life of the Zoo" where they have all sorts of creatures and breed vulnerable and endangered ones.
They have three Galapagos tortoises. They are huge. They are sisters but one of them is a bully and she eats the youngest sisters food and forces her away. This caused her to lose weight. The keepers decided to train each tortoise to a specific area to eat, using a stick with a different coloured top for each tortoise. They started by using the sticks to guide each tortoise to the specific area, giving them a treat for each successful response. It worked.