When investigating a problem with a poultry flock, the following questions should be asked:
1. What are the type, quantity, age, and source of birds on the farm? It is impor-tant to know whether any poultry on the farm is of mixed species. Some diseases can be carried by one species showing no outward signs but can be lethal to other poultry species. For example, turkeys and peafowl are particularly susceptible to blackhead, which is cause by a protozoan parasite. While the free-living forms of the protozoa cannot survive long, they can be transmitted in the cecal worm, a parasite of chickens. For this reason, it is recommended that turkeys not be raised with chickens or on ground typically used for pasture-raised chickens.