- Do they have to use living pegasus foals to do the deed? Can't they just use ones that are already dead? For that matter, dose it have to be a Pegasus? What about a Unicorn or Earth Pony?
- It's a Grim Dark fic for the sake of grimdark. Don't think about it too much.
- They actually explain that extracting colors while the filly is under pain and stress yields the best results.
- They probably could use other pony races if the situation called for it, it's just that Pegasi are the easiest to get a hold of without suspicion since they're being exiled anyway.
- Not to mention that Cloudsdale, being built on clouds, doesn't have too many Unicorns or Earth Ponies — making the rare ones "disappear" would draw attention.
Headscratchers / Rainbow Factory