ABSTRACT
Relations between agricultural animals and their surroundings always have been important. Ecology always has been at the heart of animal production. The shelter aspect of environmental management has been applied for a long time. Stress is of the environment, not of the animals. An animal is under stress when it is required to make extreme functional, structural, or behavioral adjustments in order to cope with adverse aspects of its environment. Thus, an environmental complex is stressful only if it makes extreme demands on the animal. External environment comprises all of the thousands of physical, chemical, and biological factors that surround an animal's body. The homeokinetic animal attempts to control all aspects of its internal environment via adaptive responses similar in principle to a house's temperature-control system. An environmental adaptation refers to any functional, structural, or behavioral trait that favors an animal's survival or reproduction in a given environment, especially an extreme or adverse surrounding.
