Give this A try.
Get A Walkman type radio with A headphone. Find the most obnoxious music you can find and put the volume all the way up. With the headphones connected put the radio in the attic and see if the rats leave. If not try another type of music, Classical,Rap,Country,oldies,heavy metal! there bound to hate one of them. I know I do! This has worked for me at work. A lady had mice in her file cabinet but being an extreme animal lover she didn't want traps or poison used so I used the radio and they left on there own. Where I do not know but they haven't resurfaced in the building.Never tried it on rats but you have little to lose.
If you used cat's they would have to be big mean ones. Rats fight back, mice don't. My cousin Ken had an old farm cat that was tough as nails and had the scars to prove it. He would drag home squirrels,gophers,rats you name it. I expected him to drag in the neighbors dog any day! This was not A house cat. He just tolerated Ken and hated all other humans. If you tried to pet him you were lucky if he only scratched you. His teeth should have been registered as dangerous weapons.
Good Luck!
H.R..
