Rats, Mice, Pigeons or Squirrels leave droppings and urine in the loft space, which soils the insulation and can leave an unpleasant smell.
Rodents faeces and urine can contain harmful pathogens and diseases. Most tradesmen will not go in the loft if such pathogens exist.
The contaminated insulation will be bagged up within the loft space, before begin removed from the property and correctly disposed of.
Delta Pest Control are registered Waste Carriers. You can check registered organisations via the Environment Agency