One year old hen started growing these...growths on her head. She has 4 now and they grew very fast - within a week or so. Two are on the eyes, she can't see anymore, one on the neck. We don't have a vet who could identify them. They are the size of a half walnut. She was on metronidazole for a week but they kept growing. They are hard when squeezed. Any idea what these are?