There are people who are concerned that backyard chickens will cause their neighbourhoods to become infested by vermin.
The first thing to think about is that some Windsor neighbourhoods already have a rat problem. So adding chickens to the mix won't start a problem that doesn't already exist. However there are some things to think about in order to prevent an escalation.
The first and foremost way to avoid rat problems is to keep the henhouse clear of food that rats like to eat. (That holds true for yards without chickens too, of course) Since hens and rats both thrive on the same kinds of food, it's vitally important to remove leftover food at night, and ensure the container used for storing chicken feed is kept tightly shut.
You also need to keep your coop clean, replacing the straw at regular intervals and removing droppings.
After dusk, when the hens are in for the night, shut the coop door to keep predators out.
The risk of flying predators is eliminated by covering the coop with chicken wire.
As for predators like foxes, possums, and even dogs on the loose, these can be kept at bay by digging the coop's wire fencing into the ground.
There are plenty of online resources available to help vermin-proof your yard. In the same way that responsible dog and cat owners take reasonable precautions to keep their pets safe and and their home environment clean, you can quite easily do the same for your backyard chickens.