It's okay not to exercise, but I suggest you buy the squirrel ball mentioned downstairs, because if you are too fat, rats and mice will accumulate fat, which will easily lead to lipomas and fat particle accumulation tumors, which is not good for your body and bones. Remember, mice sleep during the day and exercise at night. If they exercise forcibly during the day, they may be depressed, or lead to symptoms such as hair loss, laziness and not eating.