Skarmory is a great defensive Pokemon. (jeez, don't make your team mono-steel...)
This is what I run, to attack powerfully after setting up hazards. Don't be hating on the item, it works. But you could always use Lefties.
Skarmory @ Flying Gem
Trait: Sturdy
Adamant/Impish Nature
Stealth Rock
Spikes
Brave Bird
Roost
I'm not giving EVs since this is in-game.