Can two Shinies breed a shiny? - Quora. They can, but it's not an effective way to breed a shiny pokemon. The chance of breeding a shiny would still be 1/8192 (or 1/4096 in Gens 6 and 7), parents being shiny does not affect that*.
Does breeding two shiny Pokemon increase chances?
@qwertyk31 Breeding shinies together does not increase your chance of getting a shiny kid. About the Masuda method, both parents must come from a game with different language.
What happens if you breed two shiny Pokemon?
When these two Pokémon breed, the chances of finding a Shiny Pokémon from their egg are hugely increased. Going back to our example of Wooloo, you could therefore use a Wooloo from your own game and someone else's foreign Wooloo to have a go at hatching a Shiny one.