I'm curious as to how you foresee 4 hens in most folks backyards worse than dogs/cats/stray animal issues (eg, rabbits, coyotes, other birds)? Or maybe I am misunderstanding you?
I know I'm picking at just one point to your overall comment - but in my neck of the woods I believe our average folks are regulated more than commercial poultry businesses. While I don't live urban, all the nearby cities have started to instill urban hen policies. These policies are strict...
I think as long as you're considering how much space each chicken needs in the coop/run, you're keeping your flock respective to the space you have available, and you're ethically caring for them, then it shouldn't matter where you live.