I've been asked by a few people about my personal headcanon for Queen Chrysalis and her changelings, so here goes:
Of all the known hives, the Chrysalis Hive is the most actively aggressive. Instead of slowly draining singular ponies of their love by infiltration, this hive will actively overtake whole towns. Scouts are sent out to infiltrate military and governing positions and sabotage them. After that, a full scale attack is launched on the city, until every last citizen is captured. Victims get placed in cocoons and are only released for being fed on. Usually changelings of this hive won't bother with transformations, but instead aggressively hypnotize them. After the feast, victims are sealed up again. Being trapped in the cocoon weakens them and makes them only more susceptible to hypnosis. This hive seldomly uses husks, but usually kills and disposes of ponies who have been drained of their love.
After a city is successfully overtaken, the changelings will start occupying various cellars and other underground structures, because they prefer to live in the dark, and will start connecting them, building strange architecture, brood-chambers and decorations inside, correcting errors in the structure and improving stability. After a town is completely drained, the hive moves on to the next location. Sometimes they occupy nearby ruins and/or caves before launching an attack.
Even though they are aggressive, no-one knows why they actually tried to overtake Canterlot; one can only speculate that they got greedy. Ghost towns marked their way to the capital city, alerting the royal guard and Celestia to a possible threat.
The hive in general is pretty military and has a higher percentage of changeling commanders than any other hive. No-one knows what they eat to produce their building materials, but we can wager it is something icky. Their military nature is reflected in the way they shape their cocoons and other structures.
Through this military strength and aggressiveness, Queen Chrysalis has established herself as Queen Of All Queens, and the hive is the largest of all known hives. Their current whereabouts are unknown.
I won't be drawing this hive too often cause we've already seen the basic gist of Queen Chrysalis on the show, and she is currently being explored in the official Mlp comic book. Based on what I've seen so far, I made this interpretation. We'll see how badly it contradicts canon once more issues come out.