Do you have a registered pig? And was she in pig to a registered boar? If both parents are registered you can could birth notify and register the offspring but you would need to be a member of the British Pig Association (keeps herd book for all breeds except the British Lop, who have their own society).
What sort of pig is she?
You can just sell your pigs. Obviously, as the seller you will need to sort out the movement licences.