Section 11. If the director, or one of his agents, by examination of a case of contagious disease of domestic animals, except foot and mouth disease, is of opinion that the public good so requires, he shall cause the diseased animal to be securely isolated or to be killed without appraisal or payment. An order for killing shall be issued in writing by the director, may be directed to an inspector or other person, and shall contain such direction as to the examination and disposal of the carcass and the cleansing and disinfection of the premises where such animal was condemned as the director considers expedient. A reasonable amount may be paid from the treasury of the commonwealth for the expense of such killing and burial. If thereafter it appears, upon post mortem examination or otherwise, that such animal was free from the disease for which it was condemned, an appraisal of such animal shall be made and the amount of appraisal value therefor shall be paid to the owner by the commonwealth, except as otherwise provided in section fourteen relative to foot and mouth disease.