I am sure what @THescovieguy bought were eggs that were at half term sold by someone who was selling them so you could make "fresh" balut. So the proper question and answer that should make everyone happy would be:
Q: Are fresh uncooked eggs incubated to half-term and sold for making balut able to be hatched?
A: If they have not been allowed to cool too long or been handled too roughly and the duckling has not stopped developing they should be able to be hatched, but it would be better to get an egg that hasn't already started developing so you know the development hasn't been interrupted.