100* is way to warm for your ducklings they should be at 85* first week 5* cooler each week there after. White light does mess with their sleep cycle, but I have seen red lights in the 150 so maybe look for that watt.They are four or five days old. Their room is 71-73 degrees. When they have the red light which 250 they hide from it. They literally get as far away as possible and after a while start panting. They seem very comfortable in the white light which is 150 and lay sort of near it, but not under it, so I know they aren't cold. The themometer ends up saying it is over 100 in there when I leave the red light on for an hour which seems a bit extreme even for young ducklings. They are in a clear tote with pine shavings and a wire screen is stapled to cover a large square cut out of the lid. The light is about 8 inches up from that. Like I said, they seem very comforable with the white light. I just worry it is messing with their sleep cycles a little.