How do I make my biped mob always spawn with a pumpkin head? I'm on 1.16.5

I don't have a 1.16.5 workspace, but in the workspace I'm looking at the Mob class has a method called populateDefaultEquipmentSlots that you could try to override and add your pumpkin head there.

Thanks, I was able to do it with this

public PumpkinManEntity(EntityType<? extends PumpkinManEntity> type, World world) {
    super(type, world);
    this.setItemSlot(EquipmentSlotType.HEAD, new ItemStack(Items.CARVED_PUMPKIN));
}