All poultry going to public exhibition must originate from pullorum-typhoid clean sources and must be accompanied by a certificate of source or purchase. Poultry going to exhibition which are not accompanied by a certificate of source or purchase will be declared an infected flock by the Texas Veterinary Medical Diagnostic Laboratory (TVMDL). Organizers and sponsors of public exhibition are required to bar from exhibition any poultry not accompanied by a certificate of source or purchase.