Simple put food laced with rat poison all around the alley. If a dog or cat eats it then they are likely strays but kill the damn rats before theirs a plague or something and rabbies. Screw the eco fools you need to kill them rats because in japan and china they had rats like army ants eating everything including full size mammals and people back a few centuries ago. So respect history and get rid of the problem before it gets rid of you.

I lived above a sandwich shop in Toronto during the garbage strike. There were huge piles of trash behind the building, and the employees would go out there and beat the rats with broom sticks. There were a lot of them, and they were huge.

At the restaurant I worked in, a night manager trapped a monster rat in a trash bin and left it there. I found it in the morning when I went to pick up the stuff curiously stacked on top of the bin and it nearly jumped out and bit me. Quite the scare. Drowned the thing, wasn't happy about starting my day that way...