I found this in the Clear Creek County Zoning Regulation:
http://www.co.clear-creek.co.us/DocumentCenter/Home/View/927
1007.1.6 RABBITS AND FOWL
1007.1.6.1 The total number of such animals that may be kept shall not exceed one (1) animal
unit per one-half (1/2) acre.
1007.1.6.2 “Animal Units”...