Feral Orks are of a similar mindset to their more prominent cousins and use the same special rules. They may have mixed armour within units, use choppas, utilise the Ork Mob rule, use Grot mobs for cover, and invoke the Power of the Waaagh!
Feral Orks Special Rules
Source: Chapter Approved: Feral Ork Warband, p. 2