510 ILCS 35/4
If, upon making any tests, as provided in this Act, it shall appear that any such cattle, bison, sheep, goats, antelope, or cervids are affected with tuberculosis, it shall be the duty of the Department of Agriculture to cause the destruction thereof, in such manner as may be deemed most expedient.
The entire herd or flock may be depopulated when Mycobacterium bovis infection is confirmed in a cattle, bison, sheep, goat, antelope, or cervid herd or flock through examination of tissues at the United States Department of Agriculture Veterinary Services Diagnostic Laboratory at Ames, Iowa, or a comparable accredited laboratory, or with the consent of the owner when lesions indicative of tuberculosis are disclosed at slaughter and the tuberculin test results, herd history and epidemiological studies provide a basis for such depopulation.
510 ILCS 35/4