They should be able to go 72 hours after absorbing the yolk. That's what the postal regulations are based on. The requirement is that the chicks be shipped within 24 hours of hatch. The route they take should get them delivered within 48 hours of shipping. If they can meet this schedule the chicks are usually fine. It's when they get hung up in shipping that they run into problems.I have to look up how long she can be there without her own food..
There is nothing wrong with pulling a chick as soon as it is dried off and putting it in a brooder but you may wind up having to raise it yourself. This is a trick some people use with a staggered hatch to try to keep the broody form coming off the unhatched eggs. Sometimes it works, sometimes it doesn't. Another reason to avoid a staggered hatch in the future. Too many decisions and too much stress.