When I Used The Command /summon Zombie ~ ~1 ~ {CustomName:"OpZombie",CustomNameVisible:1,CanBreakDoors:1,Equipment:[{},{},{},{},

{id:leather_helmet,Count:1}

],Attributes:[

{Name:zombie.spawnReinforcements,Base:1.0F}

]} and others like it the zombie wont spawn with the leather helmet.