my 11 month old black austrolorp has a very large tumor on her breast. Feathers around are falling out, she looks very stressed, poor color, but other girls in coop are fine. She is on back porch now. Thing is I just noticed it today and it's huge. Up until the snow fell I was holding my Prissy almost everyday. I'm new to chickens and am worried I am missing something. Has anyone ever experienced this?