I feed on feeding day if they are blue or not. Basically I let them decide if they want to eat or not. Most do but just be vigilant and don't leave feeders in too long (if live) just to be on the a safe side. When I feed frozen/thawed I don't thaw rats for the picky eaters in blue because I know they wont eat. You'll get to know your snakes and be able to make the best calls.