That may be nest building. They build a nest by placing material on their backs while they are on the nest. It slowly builds up around them into a nest. My Aurora does that after she has laid an egg. She walks out of the coop and continues to nest build while standing and walking.Ok I’ve got one... the other day I watched one of my small red comets picking up debris (grass, clovers, pieces of bedding, dead leaves) and tossing them backwards like she wanted the stuff on her back... like she was trying to cover herself with stuff. She was underneath the coop where the food hangs. What in the heck was that all about???