Ducklings shipped with chicks, I bet that was a surprise! the temperature that ducklings need to have available to get warm, drops more rapidly than it does for chicks. by the time they're 7 weeks, they only need a spot that's 55F. Roughly 12 degrees a week, but I no longer have the specifics. However, if you have a single heat lamp, and put it at one end of your brooder, the chicks can stay under it while the ducklings might prefer to spend more time at the far end. Or if you have a heat source at each end, the ducklings might prefer to stay near the center where it's several degrees cooler. Like chicks, ducklings will pant if they're extremely hot. There are other differences, like the ducklings' need to put their bills into the water and eventually their whole head in the water, but I think for now you'll be doing great for them to try to give them a less-warm spot in the brooder. Good luck!