Cardiff fans all shag sheep as its widely accepted that that’s the national passtime in the valleys.
This is a far weirder one than Palace pikeys: you won't see many sheep anywhere near Cardiff. I could understand Swansea or Wrexham being called sheepshaggers but not Cardiff.
Re Palace, I agree with Simster: Nigels is a much better term. I lived in CP area for a while (and worked in Croydon) and I didn't see anyone who I'd call a pikey.