Final answer:
The causative agent of fowl cholera is Pasteurella multocida, a gram-negative bacterium that primarily affects avian species.
Step-by-step explanation:
The causative agent of fowl cholera is Pasteurella multocida.
Pasteurella multocida is a gram-negative bacterium that primarily affects avian species, including chickens, turkeys, and ducks. It causes a highly contagious respiratory disease known as fowl cholera, characterized by fever, ruffled feathers, respiratory distress, and sudden death.