This results, usually, in holding eggs until a pumper pair lays. Eggs can be easily held for 3 to 5 days at room temperature, before incubation has started, and placed under foster parents when the timing is right. When held, the eggs should be turned at least twice daily. Success can be achieved holding up to 10 days but success rate diminishes after 3 to 5 days of holding. Eggs held in the hydrator drawer of a refrigerator can be held somewhat longer.
Some people claim higher success holding the eggs after incubation has proceeded for several days.
I have had poorer success doing this. The developing embryo is very fragile at this time and just a little shaking can cause it's death. Also it is more sensitive to chill, in my experience. Eggs that have never been incubated usually give the best results when held. The thing to remember is to stay as close to nature as possible.