I noticed a couple days ago that my Silver Duckwing Old English Game Bantam chicken has started to lose some feathers on her chest. Today I felt her crop and it is really hard. I also looked at her legs and she has a black dot on one leg and some red sort of bumpy spots on both her legs. Right now she is in a really small cage because we are in the process of building a gigantic cage for her, we just haven't had the time to finish it. I don't know if limited amount of space caused this or what. I saw her poop and it looked normal: black and white. She is my first chicken, so I don't know much. Do you think something could be wrong with her? Also she is by herself, I don't have any other chickens. I tried to look it up online to find out, but I haven't found anything yet. If she is sick, what should I do?