...It's been observed in the wilderness, that smaller, more isolated groups of changelings, without a strong leader, would slowly become erratic, unpredictable, and much more violent, even compared to their usual selves. Their brains would revert to a more primitive, feral state, and they would lose their transformation powers.
Through our experiments, we figured out this would happen if they were deprived of love for long enough. Consuming love isn't strictly necessary for changeling survival, but if they starve for long enough, they become "feral". And if they are left in this state for long enough, they lose all sentience, and stop seeking out creatures possessing love altogether. They would hunt like a wild animal, through pure instinct, with a hyperaggressive disposition.
Eventually, such a changeling would face something much more dangerous than itself, as they also lose their sense of self-preservation. And therefore, die in the process. Such is the fate of a changeling without a hive.
But due to this peculiar nature of them, they also proved to be perfect training subjects for us. In our raids, we would capture a few hundred "normal" changelings, and keep them in pens here in the Citadel. After a few years, they would become feral, and provide an aggressive, in numbers somewhat challenging adversary. After all, even an alicorn can become a bit complacent if centuries pass without a battle...