Gharbad
I guess my key point here is that I feel Zerg is the hardest to manage while in a huge battle, simply because you have more units and they're weaker. Lurkers also add the whole burrowing issue.
Yeah, there's situations when it's not that bad, but somehow on average it just feels that way.
Actually a good Zerg player should have at least 5-10 hatcheries about mid game. Early game just keep sending out zerglings. If the enemy is smart enough to get firebats get hydras/lurkers.
In a big battle, the zerg usually lose if you get no casters.
All you have an army that can stall/damage the other army enough for you to rebuild a new one.
Then throw
that army at them.
To defeat a terran defense. If they have tanks, send in big units, Ultralisks, Unborrowed lurkers to draw away the fire, then send in zerglings. Or just drop zerglings upon the tanks.
If they have air, take a balanced force of Devourers/mutas to take out the air. If they have Goliaths, take guardians. The airforce should be about 1/8 Devs 1/4 Guards 5/8 Mutas.
If they take a group of Carriers on you, your screwed unless you were smart enough to get spore colonies/defilers.
Ultralisks are tanks, and thats what you should use them as. or use them to stop your friend whose decided to mass marines late game.
Zerg ground defenses are only meant to stall ground units while you go on an all out strike.
If you want to tech early game, make a group of zerglings and scatter them burrowed around your base. Make a small group of hydras, and use guerrilla tactics. Ambush and flank your foes.
Lurkers should be used as a distraction, to mow down infantry, or to take down buildings. always use them with hydras/zerglings. They provide easy support, and mid game use mutas with them. Have offensive units soak the damage while your lurkers get into position. or let them attack the lurkers while your other units get into position.
Zerg is all about mobility and massing. Each hatchery can spawn three or units simultaneously.