Are IVs determined before or after an egg hatches?

Question

Sorry for the awkward wording; I'm not sure how else to ask this. But basically what I'm asking is, if I receive an egg, can I soft reset before it hatches to get a better IV spread?

More specifically I'm wondering about in-game gifted eggs, such as the Happiny in D/P or the Wynaut/Togepi in RS/ORAS.

Answer 1

The moment an egg generates. In fact, IVS are calculated before the breeder has the egg in the day cares. If you save before collecting an event egg from an NPC, you should be safe.