Methods which can be used for disposal of dead animals are burning, incineration, burial, rendering, or any method using appropriate disposal technology which has been approved by the Commissioner. Disposal of animal carcasses by any of the approved methods must be completed within 12 hours after death or discovery of the carcass. Carcasses which are buried must be buried at least three feet below the ground level and have not less than three feet of earth over the carcass.