You will probably get away with not using a heat lamp. I, just today, rescued 2 little Pekin ducklings that appear to be only 2 weeks old. One has no feathers and the other just has the suggestion of tail feathers. They were seen in gardens on one road two days ago and then appeared in gardens on the next road over yesterday. They were taken in to a rear porch last night, but the night before they were out on their own with a low of 68F. The two are now sleeping in a small dog crate in my duck house. If I had raised them myself, they would still be in a brooder in the house with the heat lamp (my house is air conditioner during the day). But as they have been outside for at least 2 nights, I think it is warm enough in the duck house for them. And they are a week younger than yours. Your 4 will snuggle up close together to keep warn