I can't be sure but when Mine went broody I knew it because she didn't leave the nest and when I came near she growled and clucked at me but her comb didn't go pink till well after she went broody.
They may be getting ready to moult, maybe someone else will have a better opion on this... Good Luck
Sounds like molting to me too. How old are your girls & do you see more feathers than usual around the coop & run?
My coop looked like a chicken exploded inside of it the past few weeks. The girls are finally starting to feather out again but still aren't laying yet. They took a 3 month break last fall for molting.