Selenium (Se) is a trace element which is nutritionally essential for chickens. Selenium plays a critical role in semen quality, hatchability, egg production, and maternal programming. A laying hen requires 0.06 ppm of selenium in their daily diet to maintain egg production. In broiler breeders, a recommended daily diet of 0.2-0.3 ppm of selenium is recommended. Se comes in two forms--inorganic (selenate and selenite) and organic (selenomethionine and selenocysteine), which are both good dietary sources of the element.
USGS Selenium Soil Map
Se is an important nutrient for owners of backyard or free range chickens to be aware of, since selenium concentrations in the soil vary in different parts of the World and across the United States (US)
. China has some of the lowest concentrations of selenium in the World, as well many parts of Europe due to the large number of people who consume primarily vegetarian diets. In the US, even in the low-selenium regions, the selenium concentrations are generally adequate. Free range or backyard chickens living in areas with high selenium content in the soil may not require additional selenium supplementation.