There are definitely more queens. Couple points regarding them:
- They always seem to bulk at one base. This isn't very useful and is mostly a waste of resources. While a decent early-game defender, the real purpose of the queen I've noticed so far is for its special abilities, the most important of which is the additional larvae spawn. It would make more sense if the queens stayed spread at various bases.
- When the queens are bulked up, as mentioned in the previous point, they are tremendously good at healing each other and other units. Kudos on this. While they don't do much damage, encountering five of these makes them a real pain to put down.
- Are they using the larvae ability at all? I'm more inclined to play against a computer than watch it (having not figured out how to replay... replays) so I just don't know. This is just as critical as the chrono for protoss.