I used to put it in small red plastic flower-pot saucers, which are easy to see and to clean, under kitchen cabinets and inside open-ended covers beside walls and fences where they like to run. I used blue grains. Out of reach of pets, birds and hedgehogs. Use lots of small baits as they like to graze. You can add tasty treats like bacon scraps, peanut butter, grill fat to attract them by scent. They are attracted to pet bowls so clean up and remove after use, and clean the floor of scraps and splashes. Cats can be fed on a table off the floor. You can get waxy poison blocks which withstand damp and rain. You can buy small bags of dry mix mortar and fine concrete, though it works out dearer than big bags. Pebbles and large stones they can't gnaw through. Put poison under the shed.
They might be under the kitchen floor through gaps round pipes. Rats will fight cats.
