My hen is broody and sitting on a few duck eggs, is it normal for her to have no feathers on her chest? And it is slightly red, there are also no feathers around her nest
Its normal for broody hens to pluck their chest feathers but they usually leave them around the nest. I'm not sure if they do it to give the eggs more warmth by getting them closer to their skin and also to pad the nest though.
Yes, it is normal for a broody hen to pluck out feathers to better warm the eggs with her body heat. The skin is likely somewhat irritated, but I wouldn't worry about it unless she gets much worse or has open wounds.