Complex sentence: Some pierce the eggs beforehand with an egg piercer to prevent cracking--though others recommend against this, The American Egg Board, an industry group, recommends against piercing shells on food safety grounds: Piercing shells before cooking is not recommended.
Split into simpler sentences: Some pierce the eggs beforehand with an egg piercer to prevent cracking. Others recommend against this, The American Egg Board, an industry group, recommends against piercing shells on food safety grounds: Piercing shells before cooking is not recommended.