Strange behaviour

Hello everybody. I really do hope that your hens and roosters are fine. I found something interesting yesterday. One of my hens was was sitting on the nest and I initially though that she wants to become a mother. She was not letting any other hen to go inside the nest and she was biting me when I went to check on her. I managed to put my arm on her chest and she was warm like a future mother-hen is. She also lost a lot of feathers from her chest area and actually the skin is now clean. Even the pores are gone!!! Today she is not in the nest and she moves around with the rest of the flock. My question is, how come her body temperature was higher? And also how come she lost all of the sudden all these feathers? Change of mind? Not warm enough yet? Any help will be useful and appreciated. Thanks a lot in advance.