Question:  query regarding  incubator for the decrease hatchability 
Answer:  told him to  place the egg on the setting trey keeping the broader end upward , select the egg through candling method , the average chicken  egg wight should be 56-58 gm , elongated & round egg should not not be select for incubation  the humidity inside incubator should be in between 60-70 % of the relative humidity , the temperature inside the incubator should not exceed 102 degree f