Have never bought the Pet mince before, if Im feeding chicken I also prefer to give carcasses, necks or wings. I do give them human grade beef,lamb and pork mince though in the BARF mix. As for a bad batch, it may well be, it can happen in the supermarket meat aswell. A number of years ago I bought some beef mince for my cat and he turned his nose up at it. On a closer look, the mince was moving so I couldnt blame him really!! Supposedly freshly packed that day Hmmm, makes you wonder how much of it ended up on dinner tables that night!
No word of a lie I have only started eating mince again myself this past year it put me off that much!