xs 2 I raised an only chick. Mind you he was spoiled and out with us ALOT to keep him from yelling his head off, but he grew up jsut fine. If you are going to be putting him back in with mamma, that helps a lot too as long as she excepts him. It is better to have at least two together as they are social birds, hopefully the others will hatch.Don't listen to them!! Geez...she will be fine until the others hatch, just a couple days. If they don't hatch, then yes, I would think you could add a coupke more from the chick store as Plan B. They won't "die" right away...lol...she is just waiting on her siblings now