My snakes are juveniles. I've had them since they were about 2 ft and now they are 3ft or over. They have always shed about every six weeks. But I think it differs depending on a snake's growth, etc. Based on what you said about feeding a hopper every 3-4 days, I'd say your feedings are too close together. I would think 6-7 days would be the more generally accepted time frame.