I have a RIR who is normally very active. She started acting very lethargic today and was laying down. She shakes her head a lot like she is dizzy and if you stand her up she walks like a drunk person would and then lays down. I don't hear any wheezing and she isn't vomiting or having weird feces. She appears normal but her comb is droopy and she is exhibiting the symptoms above. Any ideas what it may be.