My cat, now 7, has worn a collar since she was a kitten - she hunts a lot so the bells at least must save some wildlife. Anyway a few weeks ago I saw that her collar was a bit tight - tighter than I'd put it on and you could see the original crease where the buckle had been and it had been moved. OH and two teens say they hadn't touched it and I trust that they didn't. So when I took the collar off I didn't put it back on as I'm not sure if someone has deliberately tightened it from outside the family.
Anyhoo, it's been off for a while but I've noticed that she has a completely bald ring round her neck - is that just because she's always had a collar and the hair has worn away or is it something more suspicious? the neck is fine btw, its not red/inflamed or sore looking - just bald.