This is quite the grand epic! But I will admit that there are parts that are quite slow making it difficult to keep my attention. I think your writing style could benefit from a little more something to keep a reader's attention. Like, sprinkle more bits of lore of the world, like product placements or accessories for meat girls. Or perhaps more emotion from the protagonist, but I can see what that might be difficult, as she was indoctrinated to believe this is a worthy sacrifice. I think it could have been very interesting if even with the indoctrination, she still had moments of sheer terror and dread and thought of running away, since she's still a kid after all and they can be quite emotional.

I wonder if I missed something though, as there is talk about how population control is a necessary sacrifice due to scarcity yet food and resources seems to be quite plentiful, enough so that many places seem to feed meatgirls for free? With all the indoctrination of a noble sacrifice, I was hoping to see the tangible effect of what that looks like for this society.

I'm so conflicted about Riley becoming a companion animal. I wanted it for her at first because there is enough here to form an emotional attachment to her and you want the characters you're invested in to survive. But then there was the scene where the boy was killed, seemingly on a whim. I found that to be quite horrific. We should value our companion animals and even right now my cat is trying to claw his way into my bedroom but I can't let him in. Killing a beloved pet for funises just feels wrong and I hope that isn't Riley's fate, to be discarded on a whim. But I do love her humane dehumanization lol. I liked her friend's mom disdainfully calling her a dirty animal, as she was conditioned to do so, yet she's also Riley and a brave meat girl and someone she cares for. The mental gymnastics required to reclassify a human is actually a very interesting part of your story.

All this to say that I'm really looking forward to book 2! I would love to see how Riley's friends and family react to her becoming a companion animal should they happen to meet.

Taking another look at the ending and I think it's the "Show not tell" thing that I'm feeling. The final bit where you narrate disappointment, uncertainty, excitement, I wasn't quite feeling it. Like disappointment might have been conveyed by Riley looking back at the butcher's room with confusion. Uncertainty, in hesitant steps back to habitat. And maybe excitement by a fast beating heart or a genuine smile she hasn't had since her watch turned red?

But I'm that guy that doesn't know what he's talking about so please take this with a grain of salt. And I totally look forward to the continuing tale!