Zinc (Zn) is an essential trace mineral needed for the formation of insulin and numerous enzymes in the chicken's body. It is responsible for the catalytic, structural, and regulatory functions in the body. Even mild deficiencies of Zn has been found to have a huge impact on the growth and development, and immune function in chicks.
In 1957, research conducted by O'Dell et al. found that when chicks were fed a low-zinc, soy protein-based diet, they had clinical signs of stunted growth, frizzled feathered, and shortening and thickening of the long bones with enlarged hocks. The abnormal leg defects caused the chicks discomfort and resulted in the birds showing a preference not to stand, spending increased time laying down.
The presence or absence of substances in foods, such as phytate, can bind zinc and make it unavailable for absorption.
Gastrointestinal dysfunction or disease may also cause an interference leading to zinc deficiency.
Recent studies have revealed that an extensive amount of changes occur in the chicken's microbiota composition when they suffer from chronic Zn deficient conditions. These changes can result in an over abundance of certain pathogenic, opportunistic bacteria to invade and cause serious disease outbreaks such as GD and NE caused by the overgrowth of Clostridium
If the deficiency has occurred for less than a 2 week duration, with prompt treatment, signs associated with the deficiency can be reversed; otherwise the chicks will likely remain deformed.