Never trust the thermometer that comes with the incubator, always check it.
The thermometer that came with my incubator was off by 5 degrees.
That could mean life or death for your babies.
Did you know "The yolk is orange and on its surface is a visible germinal disc; radiating from this area is the more watery white
yolk, which is less dense. During turning, the yolk’s structure makes the part containing the germinal disc stay most dorsal (closest to the incubating bird) for heating"
With a Forced Air Incubator (fan model) you can get the best hatch rate by keeping the temperature at 99.5º F. throughout the entire incubation period. HOWEVER, when using a Still Air incubator (no fan) at 102º F. The reason for different temperatures is that with a fan model the circulating air warms all around the egg while still air temperatures are warmer at the top of the egg than at the bottom. The temperature is measured at the level where the embryos develop (at the top of the HORIZONTAL egg). NOTE: If the eggs are in vertical position, elevate the thermometer just below the top of the egg. The temperature is measured at the level where the embryos develop (at the top of the egg). Never allow the thermometer to touch the eggs or incubator because incorrect readings can result. A high temperature tends to produce early hatches. A consistently cooler temperature tends to increase incubation times and produce weakened chicks. In both cases the total chicks hatched will be reduced. Prepare your incubator and run it for several days before adding eggs, to be positive you are maintaining correct incubation temperature. NOTE: It is common that when adding eggs the temperature will drop but should come back up to correct temperature within an hour or two. Don’t rest the thermometer's bulb touching the eggs or the incubator. Incorrect readings will result. Did you know that 10/13 day old embryos begin to produce excess heat in the incubator? Most large commercial incubators will spend more time cooling than heating!
Why Measure eggshell temperature?
CALIBRATION! YES! It’s IMPORTANT!
Calibrate the thermometer/s you are using for your Incubator. I use 3 thermometers! You need to make sure your thermometer is reading correctly, Even one degree may cause serious problems with your hatch! A simple method without specialized instruments and knowledge is to compare your thermometer/hygrometer with other devices.
CALIBRATION of thermometers:
Freezing point method.
Fill a glass with crushed ice. Add a LITTLE clean water until the glass is full and stir. Wait 3 minutes then insert the thermometer tip into the ice-filled glass so it’s in the water ice mixture. Wait a minute and if the thermometer reads 32 F then it’s accurate, and if it does not, it requires calibration.