My records for NI abattoirs that do pigs show :
ANTRIM
Ballymena MeatsBallymena, Antrim
Dunbia (Ballymena) Ltd. Ballymena, Antrim
DOWN
Finnebrogue Venison CompanyDownpatrick, Down
LONDONDERRY
Foyle MeatsLondonderry, Londonderry
Wm Grant & Co LtdLondonderry, Londonderry
TYRONE
Linden Foods LtdDungannon, Tyrone
Grampian Country Pork – Cookstown Cookstown, Tyrone
Don't have any info on sizes though