Why won't my picky cats eat their canned food or new diet?

Often providing a wide variety of foods and flavors actually promotes picky eating. If they are otherwise well I recommend you pick a one flavor formulation of high quality brand sch as hills science plan or royal canin and put down one sachet at a time, adding more if this is eaten. Cats are grazing feeders and are likely to prefer little and often, as long a s a complete balanced dry food and fresh water is available at all times they should self regulate their own food intake. Be sure to have more feed and particularly water stations than you have cats to ensure there is no territorial bullying preventing any of them from eating when they would like to