My 6 month old Serama hen has been sick for the past few days and isn't getting better. She is not eating or drinking and is lethargic. Her comb is turning darker and the feathers on the back of her head and neck are gone. Her poop is VERY smelly and liquid. She is also having problems walking on one of her legs. She has not been laying eggs while sick. We thought she had puttybutt and gave her multiple sitz baths 7 days ago. Her vent was blocked and raw, but she has not gotten better since then. We have been making her drink electrolyte water. She seemed to be getting better, but not she seems bad again. This is one of our 3 chickens that we have and we are keeping her quarantined from the rest. We have never had a sick chicken and don't know how we would treat this. Any help is very much appreciated.