Thank you for contacting the ASPCA Pet Nutrition Service, Jackie.
First, we suggest that you buy a new bag of the cat food you use and be sure to contact the manufacturer, just in case there is something wrong with the batch you are currently using.
Next, we recommend that you schedule an appointment with your veterinarian. It is unusual for three cats in the same home to stop eating at the same time, so it would be best to make sure they are not ill. It can be dangerous for cats to go without food for a couple of days, as they can develop a condition called hepatic lipidosis.