Playing Protoss vs Zerg should I target the hatchery or the drones?

As protoss, in a 'normal' - with no early rushes- I like to go 3 gate Robo and push out, with an immortal or two (if I see Roaches), or just gateway units otherwise. This normally works well and I expand behind the push, sometimes just before, and can often do a lot of damage to a Zerg's base. However not always and if I do not do sufficient damage I end up losing.

When I hit the zerg base - say with his natural expansion up and running - what should I target as a priority to deal the most damage? I normally only have small window of opportunity before mutas pop or he gets enough zerglings to surround me.

Solution 1:

In the situation you described above: Target drones.

The reasoning is because that is guaranteed damage. The drones will die; if you target the hatch, it might live and his drones can happily go back to mining after your army is killed/driven out.

Killing drones also gives you an economic advantage. With the zerg race, the player has to actively make the decision of, "Am I going to spend this larva to make a drone, or an attacking/defending unit". By killing the drone you slow down his economy, force him to spend the larva to keep up with you economically (assuming you keep making harvesters/expanding), and weaken his attacking/defending force because he used the larva to produce a drone instead of a zergling, roach, muta, etc.

Solution 2:

Not only in this situation, not for Protoss only, not versus Zerg only.

I would recommend to target harvesters in 1st turn almost always due to following reasons:

1. That is guaranteed damage; doesn't matter if it is Zerg or any other race, the opponent will have lesser amount of harvesters, lesser income, and need to spend money (and larva for Zerg, ChronoBoost for Protoss) to get new harvesters.
2. If your opponent pulls harvesters back (to safety) - you will still be able to kill gas-structures/or the "main" building (Nexus, CC, Hatchery, etc). Potentially, you could harass harvesters with quick units (hellions, bannelings, etc), but keep your main army close to the 'exit';
3. If your opponent bring some defenders, you can switch your army to shoot the opponent army... or retreat without been caught.

The only case when it makes sense to focus on Nexus/CC/Hatchery is when you have a SOLID army, but need to retreat quickly. In this case if you hunt for harvesters - you will kill 5-10 - not a big deal... (250-500 minerals). But being able to destroy those buildings - means 300-400 minerals and 100 seconds with no harvesting, that is yet 1k more minerals & 200-300 gas (on a fully saturated base). At the same time, I would not recommend you focus your army on that building alone. If you see significant forces are approaching and you need to kill more than 1/4 building health (300-500 HP), you would be better off retreating and letting your opponent defend that base. After that, try to attack from other side.