I would like to start incubating my eggs. From the time they are laid until they reach the incubator, how long a time frame do I have? And at what temperature must they remain. My coop is not maintained with heat an the temperatures in there have reached -21 celsius (-6 F). Can I retrieve these eggs for incubation or would I have to warm the coop first? The coop is wired for heat, I just choose not to.