I handle spoilers fairly well to be honest.
Heck, I used to get them a lot watching Babylon 5 and going to the Lurkers Guide to Babylon 5.
Anyhow, good work. Sorry I wasn’t in the right mindset for a bleak story, but moods like that are fickle.
I think the best part of it, for me, is how it flat out contradicts the normal “everyone matters, everyone can make a difference” mentality I’ve seen and heard from so many people in so many different walks is life. There’s a lot of things that will happen that will never be more than a blip on the radar of other’s lives if even that.
The cry “I am not a number!” falls flat when, in the end, you end up a statistic to be ignored or passed by.
I’m not gonna say you had a particular metaphor here or something expressly to be said about power structures and those in them. I don’t know your working or you will enough. Narratively speaking the poor foal was doomed, and I don’t think you could’ve done otherwise without changing/violating what was done before. It would’ve been a cheaper ending, I think. A switch and bait.
Again, good work!