You’ve likely seen the news reports over the last year that rats are increasing due to COVID. Conditions have changed with restaurant closures, businesses being shut down, and more people working from home. While food processing and storage facilities haven’t experienced those same shut downs, rodent pressure has been higher at your site, and likely will continue to be higher in the near future.
Rodents moved to your site from other areas. Nearby areas that had plenty of food resources for them like restaurants, hotels, and more urban areas had foods and food waste dry up. Rodents like rats and mice moved to areas with more food resources. That means food processing, food storage, and more suburban and residential areas. Like all living things, rodents need food, water, and shelter. When their food sources are reduced in one area (no more loaded urban dumpsters), they search for other areas. With more rodents on the outside, the chance of them getting inside (where all the good food and shelter is) increases. That increases the chance of damage from rodent feeding and gnawing as well as the risk of contamination from feces, urine, and the diseases rodents can carry.