Cockatrice Map Location
Slayer Gear Required for Hunting Cockatrice
Bring your Mirror Shield, Buy it from your Slayer Master (5k GP)
Best place to farm them is the Fremennik Slayer Dungeon. As i dont have the fairy rings or whatever, i usually just tele to Camelot and then walk north to Relika and then east to the dungeon entrance, its a bit of a walk but not too bad.
Sometimes drops Medium Clue Scrolls and Mystic Boots (16k GP), lots of limpwart roots.