Oh, the things we do for love, and for feathered friends with questionable digestive choices. Here we have a teen, clearly a conscientious soul, staring down a Friday adoption like it's a final exam in Chicken Health 101. Cold feet. A bout of brown, not-quite-runny diarrhea. And a whole classroom of chicks who have been breathing the same air, pecking the same feed, and very likely sharing whatever bug the little one might be carrying. I get the worry. I really do. When you're about to bring a living creature into your family, and that creature is small enough to fit in your palm, every sniffle or loose stool feels like a five-alarm cluck-tastrophe.
Here's the thing: cold feet in a chick can mean a few different things, and not all of them are the stuff of nightmares. It could be a sign of dehydration or an electrolyte imbalance, which you're already on top of with the electrolytes plan. Good instinct. But it can also be a sign that the chick is simply chilled, stressed, or not eating enough. The fact that the diarrhea was only one episode, with no blood, and was not super runny, leans toward a mild upset rather than a full-blown contagion. That said, the chick has been in constant contact with its classmates, so if it had something truly nasty, you'd expect to see more sick birds by now. The absence of a classroom full of ailing chicks is actually a pretty good sign.
Now, the practical question: do you pick up the chick early, or wait until Friday? I'd say pick it up tomorrow if you can. Not because I think the chick is on death's door, but because you are clearly losing sleep over this, and stress is not good for you or the bird. Early pickup gives you the chance to isolate the chick from your other two adoptees once you get them home, even if the school can't quarantine it. And honestly? A calm, warm environment with electrolytes and close observation is often better than a classroom full of noise and wing-flapping competition. Your family member who will take this chick will thank you for being proactive. Plus, you'll feel a thousand times better knowing you did everything you could.
You've got this. Your worry is proof that you care, and that care is exactly what this chick needs. Move up the pickup if possible, keep the chick warm and hydrated, and watch for any return of symptoms. If it thrives, great. If it doesn't, you're already ahead of the problem and can call a vet. That's not chickening out, that's being a responsible chicken parent before the bird even crosses your threshold. Go get your little cold-footed friend, give them some electrolytes, and let them know they're coming home to someone who actually pays attention. That's more than most chicks get.