If that is the temp it's way too high for ducklings, chicks yes but ducklings don't need that high of heat. Most of us start ours out at 85 and each week go down 5 degree.
They sure are adorable little twins ♥️
You really need to place mama hen and the rest of the eggs in a safe part of your coop, you can make something using scrap fencing lattice or what ever you have but to keep her and the ducklings safe they should not be in the general part of the coop.
As for the duckling I think silver spray...