Zerg is kind of funny in that almost everything has a penultimate form: all units start out as eggs, and all buildings start out as drones. The nice part about that is that this means that things can be on control groups before they’re done. I see this being helpful in 2 ways.
First, you can put buildings on a group before the drone makes its way to the final position, which the other races can’t do. I’ve been thinking that one thing I can do is to put all of my tech buildings (spawning pool, evo chamber, spire, everything) on 0. That way, I never have to look at a building to start upgrades. This becomes very easy if I get in the habit of adding the drone to 0 when I send it to build.
Second, you can put eggs in a group before they’ve hatched, which other races can’t do (except maybe off of warp gates). One of the big mistakes I often make is bad rally points, either sending units to the enemy base long after an attack has ended, or not rallying new units to a push. While practicing my 10 pool (very necessary for multiplayer games), I started adding lings to my attack group once they were turned into eggs, which worked really well. This is also a relatively easy habit to get into: once you build all of the eggs you want, control-click them at the bottom to select only the new units (wouldn’t want to add larva to the group!), and then shift-add them to the right control group.
I think I have seen ViBE do both of these things before, but he also has insanely high APM, so it might be tricky to execute regularly.
There are a couple of things to be wary of with adding eggs to control-groups is that you can’t attack-move eggs. They’ll ignore any A-Move orders, and if you want them somewhere you’ll need to regular-move them. You also need to be careful of their movement when they hatch, as they’ll run to wherever you last told the group to move to. It’s quite easy for them to get picked off if you’re not mindful of this. However, I think it’s usually better than the alternative. I don’t use it if the units are going to be in a delicate situation, such as when I’m harassing with mutas. I have the new mutas waypointed to a safe area, but don’t add them.
That’s a really good point. I think that problem goes along the same lines of rallying hatches to the front, retreating, and watching as units continue to stream across the map into the enemy army.
I think mutas are a good example of an exception unit. I’ve had them fly straight through marines as they try to meet their buddies harassing the mineral line behind enemy lines.