How long can I hold out eggs before I put them in the incubator? I need to save some to fill up the incubator, but I don't know how long I can keep them out. What do I need to do with them while I am holding them? I have four hens, I get about 7 eggs every couple days (one hen is young and doesn't lay regularly yet). I am getting a 40 egg incubator from Tractor Supply. I want to mostly fill it up when I run it.