The cat has started farting, very smelly farts. We've wormed her (Dropcit), she doesn't usually hunt much but we've had an epidemic of flytipping household waste around the area. Could she be getting into something? It has been a bit better since the first dose of wormer but she's still doing the odd one. We're due to give her the next in around a week or 2. She's never done this before (she's four) and otherwise she's healthy with a good appetite. What could it be? Any ideas?