When is the ability of an Pokemon determined while hatching eggs?

Question

So I just beat Pokemon emerald and thinking to do Pokemon platinum next then I realised I need a good flying type.My options are
staraptor
crobat
togekiss
Now I can just get the other 2 with the right ability but I want togekiss mainly because I used staraptor in dimond
and crobat in platinum run 1.In this run I want to use togekiss and so I need to know when the ability is determined because if I get hustle its terrible for togekiss and serene grace which is op for togekiss.I want serene grace but don't know when the ability is determined whether it is pre determined or determined when the egg is hatched so please help or else i'll have to go for the other 2.

Comments

I think it's determined when you receive the egg, but I'm not entirely sure.

Answer 1

Every detail about the Pokemon is determined when the egg is received. This includes shininess, ability, nature, IV's, Egg Moves, etc.

Game Freak did this so you have to repeatedly hatch eggs to get the specific Pokemon you want, instead of just soft resetting over one egg. You obviously don't see Shiny Hunters saving before an egg hatches to reset over it, because that is 100% pointless in every way.

Source: experience

Comments

How do you know it's not determined when the egg is laid?

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When the egg is laid, you receive it.... Do you mean when the egg is hatched?

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When the egg is laid, the day care person steps forward, turns around, folds her arms, or something like that. When you talk to the day care person after the egg is laid, you receive it. They don't happen at the same time.

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That's true. Ill test it but I don't think that is the case

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... Both Nincada that I hatched were Sassy with Compound Eyes. Interesting tho, I never knew this

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The egg is determined when you accept the egg, not when it’s laid

Source: experience

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I tested this and this is not true, unless I got the same nature twice in a row

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you probably got the same nature twice