Skarmory @ Leftovers Ability: Sturdy EVs: 252 HP / 232 Def / 24 Spe - Stealth Rock - Whirlwind - Roost
defog isn't an option since oras doesn't have a move tutor for it :I
Your Skarmory is can easily be take down with Taunt. I would suggest an offensive move so that you will still be able to do something even if you are taunted
Brave Bird
Good power 100% accuracy unless accuracy is lowered and STAB. The only problem with this is that if you are taunted you won't be able to heal up with Roost. But if you aren't taunted I would use Roost to heal up as Lefties alone might not be able to recover what you've lost and Skarmory needs to be a healthy health to do its job.
Iron Head
Good power and STAB also a chance to flinch.This again is another move so that you aren't stranded helpless while in Taunt mode
I think fly would be good since you can fly around on it plus if your playing a wifi battle against someone with a rayquaza and they use dragon ascent you could be in the air and they don't hit you since you used fly.