I have two eggs and we are about half way through day 21. One hatched around 11pm last night, the other hasn't pipped yet but I've seen the egg wiggle. How long can I keep the first one in the incubator waiting for the second? My last hatch the only egg that hatched was day 25. If I have to move it under the broody, can I add the second one later if it hatches in a few days time? She is a really placid broody btw.