Don't listen to the Angry Birds wiki (Foreman Pig and Large Pig, Medium Pig and Small Pig and all that). Only trust the official Angry Bird Toons series and the official book; 'Official' Angry Birds Annual 2013. Anyway, this is the answer to your question:
The Pigs are called Bad Piggies. These are the only Bad Piggies there are so far:
King Pig (not the King or the Pig King), Moustache Pig (not the Foreman Pig, Grandpa Pig, Mayor Pig or Father Pig), Corporal Pig (not the Helmet Pig, Soldier Pig, Armour Pig or Major Pig), Minion Pigs (not the Small, Medium and Large Pigs), Postman Pig (not the Mail Pig), Mechanic Pig (not the Pig Mechanic), Professor Pig (not the Scientist Pig) and Chef Pig (not the Pig Cook)
It is unknown what the official name of the Freckled Pig is called.
That should be a satisfactory answer to your question.