They don't "add" omega 3 to those. They are simply eggs as they should be, laid by free-range chickens instead of a caged up, unhappy animal that is being fed worthless feed. The feed that is given to the caged chickens is so lacking that the final eggs' omega 3 content is far below par when compared to what it naturally should be.
You threw away perfectly good eggs. You should have tried them first. They are so much tastier than the factory produced stuff that it would have been a good reminder how poor the mass produced stuff has become.