I am also trying to rehome 4 ducks! They are all 7 weeks old. 2 are welsh harlequin (males I think) and the other two are welsh harlequin x blue Swedish mixes. they are very pretty but I sadly don't have enough space for them. If you would like them PM me.
Do you have a thermometer under the heat lamp? Are all the chicks crowding under it or on the other side of the box? Have they drank and water and/or ate any food?
Short version: A raised waterer helps tremendously!
Long version: When I go my first batch of chicks almost 2 years ago I had one of those plastic waterers which work fine but it kept getting super messy on the ground. I has to change their water multiple times a day and it was a huge hassle...
Great! Just made a paludarium (fish tank with land and water) and added fish and snails. I am adding more animals like a turtle, a gecko, shrimp and more soon! How have you been?
Is she wet? What is the temperature in the brooder? Try putting some electrolytes in her water and feed her wet starter. Try force-feeding her the wet feed.