Do you have a thermometer under the heat lamp? The lamp looks a bit too close to them, and I would raise it to at least 18 inches or more from the tops of their heads. Also it is good to double secure heat lamps, and I use the cord sometimes and wrap it around the holder once, usually a 2x4 which helps to secure it. The temperature should be only 80 degrees or less in the hottest spot for a 3 weeks old. You cannraise the heat lamp to reduce the temp.