This is my first attempt, I have built my own styrofoam incubator using a water heater thermostat, computer fan and 40 watt light bulb. I would like to try some free chicken eggs (bantam, rhode island reds, silkies) that I got but was wondering if anyone can tell me if their temps rise and lower when light shuts off and on or does it stay a steady temp with no fluctuations. For example I kept record: light shuts off at 102. then turns back on at 95, This was using a stick thermometer. Is it ok to vary that much? Or should I higher or lower it or leave it where it's at?