Test my eggs for fertility on the evening of the seventh day. Do not test in a very cold room. If you think they will get too cold before you finish testing, carry them to a warmer room to do the work. Take out one tray at a time and close the machine, turn the lamp up a lit tle so the egg chamber will be quite warm, when you return the eggs, and it will not take them so long to get back to their proper temperature.