Pigs ears are like bones to dogs,they become very possessive and aggressive if you go near them.Your pup is still very young and should learn if you guide it right.My dog used to snap if I went to touch his pig ears/bones or other dog treats,now he growls rather aggresssively but wont bite me if i take it.
I wouldnt worry about it too much,just let him/her know biting is wrong and the pup should learn.