Question

If I have a female Kakuna and I want to breed for a weedle with its hidden ability what are my chances of getting it?

Comments

you need a Weedle or Beedrill with it's HA, so without that, none

Answer 1

Starting in Black and White, female Pokémon with Hidden Abilities have a 60% chance of passing on the Hidden Ability to their offspring when bred with a male Pokémon from the same Egg Group. In Generation VI, this was extended so that male and genderless Pokémon with a Hidden Ability can also pass it down if they are bred with Ditto. The chance of the offspring having either non-Hidden Ability is 20% each.

Kakuna doesn't have a hidden ability, so the chance is 0.
source

Comments

The chance isn't zero as the ability slot concept applies here; if a Pokemon is spawned to always retain the ability in its species' Hidden Ability slot, it will always keep it. So basically, if a Weedle has its Hidden Ability, it will evolve into a Kakuna with its Hidden Ability (which of course doesn't exist). Therefore, when it evolves into a Beedrill, it will retain its Hidden Ability slot. If that made no sense: http://www.gamefaqs.com/boards/696959-pokemon-x/68206451
The probabilities are correct though.

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The slot concepts only apply with the two regular abilities, not the hidden one. http://pokemondb.net/pokebase/176907/why-does-my-dustox-lose-its-hidden-ability-upon-evolution

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Woah I just contradicted my own answer.
That's really dumb, Pokemon should be able to keep their Hidden Abilities through evolution. :/

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That's really dumb, Diglett shouldn't be able to learn aerial ace. :/