Section 13A. All sheep and other domestic animals which are affected with, or have been exposed to, scrapie shall be destroyed when, in the opinion of the director, the public good so requires, and their carcasses shall be buried or otherwise disposed of. An order for killing and for the disposal of carcasses shall be issued in writing by said director, and may be directed to an agent, inspector or other person. The director may appoint persons to make appraisals on live stock, the destruction of which is ordered under this section, and fifty per cent of the full value of such live stock, as determined by the appraisal, may be paid from the annual appropriation for the extermination of contagious diseases among domestic animals. If the federal government appropriates monies for payment of a certain portion of the value of any animals destroyed under this section, the amount of payment by the commonwealth for such animals shall be limited to the difference between such federal payment plus the net salvage received by the owner, and the full value as herein determined, which amount shall not exceed fifty per cent of such value.