If you hatch later than 21 days it mean your temperature is too low.
Your termometer is not correctly show the temperature.
you need to calibrate it with better termometer
my next guess your temperature is not even. maybe your fan is not on the right position.
I did not see where is you fan
Your termometer is not correctly show the temperature.
you need to calibrate it with better termometer
my next guess your temperature is not even. maybe your fan is not on the right position.
I did not see where is you fan