Pokémon Sun and Moon has seen some changes from the previous Generations and that includes the introduction of SOS Battles. In Generation VII, there are two ways of getting a shiny Pokémon and that is through breeding and adrenaline chaining (SOS) method and today, we're going to explain the exact odds of rolling a shiny as well as obtaining hidden abilities and perfect IV Pokémon.
Chain Length 0 to 9: 0% chance of Hidden Ability
Chain Length 10 to 19: 5% chance of Hidden Ability
Chain Length 20 to 29: 10% chance of Hidden Ability
Chain Length 30 to 255: 15% chance of Hidden Ability
Perfect IV Pokémon
Chain Length 0 to 4: No guaranteed perfect IVs
Chain Length 5 to 9: 1 guaranteed perfect IVs
Chain Length 10 to 19: 2 guaranteed perfect IVs
Chain Length 20 to 29: 3 guaranteed perfect IVs
Chain Length 30 to 255: 4 guaranteed perfect IVs
As mentioned above, there are two methods of obtaining a shiny and that is via breeding and SOS method. Now, as most of us know, the Masuda Method still exists in Generation VII and the new data reveals the exact odds of obtaining shinies from both methods to finally answer the question: "which is better, hunting or breeding?"
Shiny Chance: SOS Method
Now before we get started, it's important to note that chaining actually increases the odds of encountering a shiny Pokémon. The data below will show how the 70th and 255th encounter will yield a higher chance of encountering one.
Chain Length 0 to 69: unknown
Chain Length 70 to 255: Three extra rolls for a shiny spawn
According to Penguins rock, the 70th encounter will yield an extra 3 more dice to the overall shiny RNG of 1/4096 which means that your 70th encounter gives you a 4/4096 or 1/1024 chance of finding a shiny Pokémon. With the Shiny Charm, this number is doubled which means that you'll have a 6/4096 or 1/683 chance of finding a shiny Pokémon upon your 70th encounter. (*Note:The 70thencounter refers to the 70th Pokemon that was called in for help)
Now assuming that the Masuda Method in Pokémon Sun and Moon is the same as from Gen VI, it's safe to say that with the help of Shiny Charm, the odds of breeding a shiny goes up to 8/4096 or 1/683, which is a lot higher than the odds of encountering a shiny Pokémon via SOS method.
What Breaks the Chain
Knocking all Pokémon in the field
Knocking out the original caller, Only If there are no evolutionary relatives on the field. (e.g. knocking out Pichu when the enemy's side only has Pichu and Happiny.
What Doesn't Break the Chain
Switching out your Pokémon during battle
Knocking the original caller as long as the ally called is within the same evolutionary tree.