The answer to 'why is my rat swarms' is that you likely have a serious rat infestation on your hands. Rat swarms, or large groups of rats, are usually a sign of a growing population and can indicate a significant pest problem. Rats are highly adaptable and can thrive in many environments, especially if they have access to food, water, and shelter.
Some common causes of rat swarms include improper food storage, clutter or debris providing nesting sites, and entry points in your home that allow them to get inside. Symptoms of a rat infestation may include droppings, gnaw marks, nests, and even sightings of the rats themselves, especially at night. To solve the problem, you'll need to eliminate their food sources, seal up any entry points, and use traps or poisons to reduce the population. However, for large-scale infestations, it's best to call in a professional pest control technician who can safely and effectively get rid of the rats.