Frequently there is confusion as to how the measurement of humidity is expressed. Most persons in the incubator industry refer to the level of humidity in terms of degrees F., (wet-bulb) rather than percent relative humidity. The two terms are interconvertible and actual humidity depends upon the temperature (F.) as measured with a dry-bulb thermometer. Conversion of the two humidity measurements can be made using the following table:
Wet-Bulb Values For Four (dry-bulb) Incubation Temperatures
| Relative Humidity |
99o � |
100o |
101o |
102o |
| 45 |
80.5 |
81.3 |
82.2 |
83.0 |
| 50 |
82.5 |
83.3 |
84.2 |
85.0 |
| 55 |
84.5 |
85.3 |
86.2 |
87.0 |
| 60 |
86.5 |
87.3 |
88.2 |
89.0 |
| 65 |
88.0 |
89.0 |
90.0 |
91.0 |
| 70 |
89.7 |
90.7 |
91.7 |
92.7 |
| Species |
Incub. Period Days |
Temp (F.)� |
Humidity (F.)� |
Do not Turn After |
Humidity Last 3 days� |
Open Vent More |
| Pheasant |
23-28 |
100 |
86-88 |
21st day |
92 |
20th day |
� Measured at degrees F. in a forced-air incubator. For still-air incubators, add 2-3 degrees F.
� Measured as degrees F. using a wet-bulb thermometer. Use chart to convert to relative humidity.
Sanitation
In large commercial incubators, eggs of different ages are often set and each setting transferred to a separate unit prior to hatching. Separate hatching units permit proper sanitation and disease control measures to be practiced between batches of chicks. The chicks can be hatched without disturbing the other incubating eggs.
Thoroughly clean and disinfect the incubator and hatcher before each usage. Remove all egg shells, down, dust, and extra material with a broom or vacuum. Wash the unit with a warm detergent solution and rinse with a disinfectant solution. When dry, turn the units on and bring to proper temperature and humidity conditions prior to filling with eggs.
A thorough cleaning job results in a 95-99% improvement in disease control. When done properly, little or no disinfectant is needed. If a disinfectant is used, quaternary ammonia is the most commonly used disinfectant for equipment like incubators and hatching trays. "Quats" are relatively non-irritating, non-corrosive, of low toxicity, and is reasonably effective in the presence of organic matter. Since the incubator and its components should be clean and free of organic matter before disinfectant application, quats are a good choice.
Fumigation is another tool for disease control and is something good to turn to when either the cleaning is poor, eggs are dirty, or machines are filled with eggs and it is difficult to empty and clean properly. The fumigation process can be hazardous to the producer if not conducted carefully. Contact your local County Agent's office for additional information on properly fumigating incubators and hatching eggs.
Trouble Shooting Failures
The novice poultry producer will usually encounter problems when incubating the first batches of eggs. Fortunately, causes for most failures can be diagnosed and corrected. A separate diagnosis chart has been prepared to assist in solving incubation failures. Refer to this chart at Trouble Shooting Incubating Problems