Incubating and hatching conditions
Poor results are most commonly produced with improper control of temperature and/or humidity. Improper control means that the temperature or humidity is too high or too low for a sufficient length of time that it interferes with the normal growth and development of the embryo. Poor results also occur from improper ventilation, egg turning and sanitation of the machines or eggs. Obtain the best hatch by keeping the temperature at 100 degrees F. throughout the entire incubation period when using a forced-air incubator. Minor fluctuations (less than ½ degree) above or below 37.5 (incubation) and 37.0 (hatching) degrees are tolerated, but do not let the temperatures vary more than a total of 1 degree. Prolonged periods of high or low temperatures will alter hatching success. High temperatures are especially serious. A forced-air incubator that is too warm tends to produce early hatches. One that runs consistently cooler tends to produce late hatches. In both cases the total chicks hatched will be reduced.