Folks, I'm not talking about processing. I am using them as livestock (which I've done before as a hive mind). I'm not eating them up. If that is what is happening, then it's a bug. But I don't think that's what happening, as they stopped declining at some point.
They might be migrating away(There was a blue flag for the Livestock that tells you a bit more)
The blue flag is the -20% happiness for being conquered. I did conquer them fairly recently, although I resettled most of them to new planets to dilute their anger until I nerve stapled them.
Also, for the OP, pop growth mechanic are still wanky as hell, did pop decline stop when your pops arrived at parity ? (50% livestock 50 % hive mind main specie. Assuming you haven't assimilated anyone of course).
They did stop declining, but it couldn't have been parity since they were in the minority on all planets after a massive resettlement program.
What does 'Base decline' mean?
Yeah, I have no idea. If I knew what it meant, I could at least know what is causing the decline, and why it stopped.
I've (rarely) seen enslaved pops with migration controls enabled emigrate on low-habitability planets as well in my current slaver game, so something is certainly buggy.
I did wonder if it was habitability at first, but they have 100% habitability.
The decline doesn't originate from the livestock slavery type, it originates from the fact that you're a hive mind and they're non-hive mind pops on a hive mind world. Nothing you can do to prevent it, except for integrating them into your hive, at which point I think you can no longer use slavery on them.
No, it's not that either. None of my worlds are terraformed to a hive world. I've done that before (accidentally) and wiped out my livestock via hive world terraforming. (I forgot to resettle the livestock to my habitats.) If you have a normal world, the livestock for a hive mind are treated like any kind of livestock in a normal empire, except they have stricter restrictions on migration and reproduction.
Again, what's weird is that the decline just magically stopped at some point. I have stable livestock populations again.
I guess I should bug it, but I don't even know what to tell QA.