If not Bumblefoot or SLM what else could it be?

[NewAtThisinTN]

I have an almost 3 month old Barred Plymouth Rock that isn't doing too well. Last week I noticed she developed some sores on her legs and was favoring them. I did some internet searches and assumed I t was scaly leg mites and started treatment with vinegar-based soaks/scrubs and Vaseline. I did this consistently and the problem has only gotten worse. She is now very lethargic and her stools are greenish and very runny. She doesn't have anything on the bottom of her feet (no brown spots or cores) and I don't know what my next move should be. I assume antibiotics of some sort. I plan on going to my co-op tomorrow for help/suggestions but I thought I'd check with you all here first. Any advice would be much appreciated.