Awe........... I don't know whats wrong with her but she is sick. I would assume it is a respritory illness and very contagious till I knew differently. I would definiately keep with the antibiotics until someone can tell you what else to do. Did you seperate her from the other chickens? I would definiately do that too if you haven't already . Is anybody else getting sick at all? Are you treating her by herself or are you treating the whole flock? I personally would treat the whole flock, but some might tell you don't treat unless you know for sure the others are coming down sick too. I hope she gets better soon and


best wishes, Sandy
Is her nose runny , her eyes look clouded over in the video but I couldn't tell what was up with her nose and her mouth seems to be filled with mucus???
Did you use something new in the coop? bedding, or a new feed, is there any mold or does your coop leak? Mold can be deadly to chickens.
I would check just to make sure there weren't any damp spots just to err on the side of caution.
I also would probably take her in the house with ya and fix her up a little box with a blanket just to make sure she stays warm and is getting food and especially water, I know when I get sick I just don't want to eat but it is very important for her to eat to keep her strength up also how old is she and is she laying eggs?