Poultry fowl are susceptible to the following pathogens
(a) Viruses
(b) Bacteria
(c) Fungi
(d) All of the above
Poultry fowl are susceptible to a variety of diseases caused by different pathogens. The different pathogens which cause these diseases are mentioned below:
Bacteria: Diseases such as Fowl Cholera, are caused by Pasteurella multocida which is a type of bacteria.
Viruses: Diseases such as Avian Influenza, caused by virus–type A Orthomyxoviruses.
Fungi: Diseases such as Aspergillosis caused by mold which is a type of fungus.
Hence, the correct answer is D.