Incubators

Incubator, an insulated enclosure in which temperature, humidity, and other environmental conditions can be regulated at levels optimal for growth, hatching, or reproduction. There are three principal kinds of incubators: poultry incubators, infant incubators, and bacteriological incubators.
Poultry incubators are used to keep the fertilized eggs of chickens warm until they are ready to hatch. These are the oldest type of incubators; rooms heated by fires were used by the ancient Egyptians and Chinese to hatch chicken eggs, and later incubators used kerosene lamps to heat air or water in proximity to the eggs. Modern incubators are rooms heated by electricity. Large electric fans circulate the air to maintain uniform temperatures, and the eggs are turned automatically at least eight times daily. The larger commercial incubators may hold as many as 75,000 eggs at one time.