2nd Gen Shiny RBY exclusive Pokémon- How?

[Red1530]

That highly depends. You're either very lucky or you're manipulating the RNG.
The rate for breeding a shiny is exactly the same as wild encounters, 1 in 8,192.
I don't believe that the Masuda Method can be used in HGSS either but please tell me if I'm wrong on this.
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The Masuda Method works in all Fourth Generation Pokémon.

 

[Weavile05]

How many eggs you breed has no relation to the chance of getting a shiny.
However, in DPP, when you chain, the higher your chain goes, the more likely you are to get a Shiny. Once your Chain hit's 40 it's pretty much Garunteed.