I give this same advice at least once week. We have a member here who's written what I believe is the best info on intervening in a hatch. This information has helped me save the lives of some expensive and low-cost birds. There are many here who believe that we are producing birds that would be better off dead when we help birds hatch. Nearly every bird that I have assisted has become a healthy and strong specimen! Here is a link to Pete55 page. Once there, you can link to several of his articles.