Is my chicken sick?

[stargirl]

How's she doing now?

 

[ELLY1]

Hi Im from the uk my xbattery is all fluffed up has been for a week and its NOT because of the heat, my other chicken if fine, she also sits on her own eats little and looks sad.I have dusted the coop for red mite and dusted them for red mite and lice but she still not right, dont know what to do now