We've fostered cats for years but don't have much experience with unneutered female cars unless they're still feeding kittens. But we have a single female cat at the moment, who's normally very placid but has been stroppy and a bit nippy this week. She can't be neutered yet for various reasons not related to her health but I can hear her "singing" this morning sou think she's about to come into season. Could the bad mood be PMT?