The rabbits are us in the way we live our entire lives separated from death only by our domestic routines of normalcy and our denial. Rabbits are bred for the slaughter; they live their entire lives in their little cage, surrounded by, and fed by, the very same people who will someday unthinkingly break their necks.
They're traumatized by the collective memory of past relatives being snatched from their cages while the characters themselves were still too young to fully comprehend the severity and reality of what was happening. The horrors they witnessed so long ago are now just an underlying feeling that something is wrong. They, and we, live their entire lives among death, ignorantly and purposely oblivious of it, until the one day when they are able to ignore it no more, until the day it is their turn.
That's what sense I made out of it anyway.