I got it last June and never used it. I didn't see a date on the bottle. Should I use it or buy a new one? Also my buff opington seemed different today. She didn't come outside for a minute after I opened it up, and she seemed like slghtly off balance. She's moving her head more than usual too. (You know, the chicken head bop) Also, she wasnt running as much. But she's eating and everything. I don't know how to describe it, something just seemed off. Does it sound like anything?