Yeah that's what I have as well. LIke I said, i kept my temps around 100-101, and the chicks hatched 2-3 days early. If the temps are a little low, it makes them hatch late, and if they are high, the chicks hatch early. I also have bantams, which I have also been told hatch early, but with my second hatch, I kept the temp closer to 100, and only one hatched early(day 18), the others were on day 20-21, Just make sure that you have the sensor part of the thermometer even with the tops of the eggs. You could also make a water wiggler. Take a ziploc baggie fill it about halfway with water, and stick it into a toilet paper roll. Use an old mercury thermometer, and stick it into the inside of the baggie, between the two sides. This represents the temperature of the inside of the egg. As long as this is close to 99.5, then you should be ok. It would set at the same level as the eggs. Good luck!