How many people do rotation diets? Have they worked? How many/what brands do you rotate through? How often? Do you switch cold turkey or do it gradually? I have Finn on Wellness CORE (puppy formula) right now, but I would like to get him on a rotation diet. Maggie has been eating Blue Buffalo for a couple of years now, and she's starting to get bored with it, so I'd like to vary it up with Finn.