Well they have definitely been exposed to whatever she had, so it wouldn't hurt to at least have it on hand. But she might have just been not as resistant to it as the rest. I've lost a few that just lacked the vitality of her siblings; weaker immune system and cold weather brings them down and culls them for me sometimes, unfortunately.
If anything, I would keep a very close eye on them, and maybe pick up a small bag of medicated starter so if it wasn't cocci, they can go ahead and get exposure so they can build immunity.
If there are no signs of illness in any of the others after a week or so, then you can probably rest a bit easier that they'll be OK.
Do keep a look our for blood in the stools, as that can be the first clue something is amiss.
I'm so sorry you lost her, my condolences