Hi, one of my Black Astrolop pullets, since yesterday, has some strange behavior. She is backing up into corners and appears to be trying to scratch/pull something from her chest, or legs. It started yesterday. I cannot see anything with my eyes, she does not appear injured. The rest of the flock, same age, all appear just fine. Any insight is appreciated. ( we only have 14 pullets, all came together, all appear fine and healthy. I'm pretty meticulous with bedding/feed/water etc.)