It took me forever to figure out the regulations in NYC (Brooklyn, Manhattan, Queens, Bronx, Staten Island), but they are actually quite simple:
1) NO Roosters (seems justified given the noise complaints)
2) Keep it clean
Basically in NYC the issue is that the health department has to be able to come over and make sure that you aren't creating a health hazard for neighbors. There are no numeric limits (that I'm aware) in terms of number of birds, but there are definitely practical limits if you have a small urban lot. I would not recommend doing chickens on a roof because there will be a surprising amount of manure, and unless your roof is really setup as a green roof that can support an extra cubic yard or more of chicken compost (manure + hay/wood shavings) every 6 months then you will end up having to cart things down, which I think would be a major logistical hurdle.
If you have a small flock (you need at least 3 chickens for them to be happy, but I would recommend less than 8 - we've kept between 3-6 on our 1/10th acre lot), then the main concern is keeping the smell down. It also helps if your coop and the surrounding area always look very clean/tidy - we've had at least 6 visits from the health department over the last 4 years (one of our neighbors apparently doesn't like chickens), but every time they have arrived they've looked out over a very clean coop, happy chickens and a neat backyard and said "this is not even close to a problem" and walked right back out. As usual when interacting with the department of making you sad, it's best to be polite and helpful. The health department in NYC sees so much crazy stuff that if you are even making a halfway effort you fall under their radar.
I've found two very effective ways of reducing the smell from chickens:
The first is Big Ole Bird Biology optimized for birds
- which is actually derived from the Aloe plant. It completely neutralizes the ammonia in the manure, in addition to helping with egg production and some diseases (or so it claims, we've had no problems so it can't be hurting). You put a capful in their water every few weeks and it starts working within a few days.
The other is to do deep bedding. This means you want to avoid putting your coop on top of concrete if you can avoid it. It will probably work if you have to put the coop on concrete, but you will want 12+ inches of woodchips (I've seen no adverse effects from either cedar
or pine chips
despite claims on the internet) to start the cedar chips are a bit cheaper online, so I'd probably default to those. What you will do is take a pitchfork or a shovel and turn the chips every week (you can go longer in winter). Every 4-6 weeks you will wnat to add another bag of woodchips. This has two awesome impacts: smell goes away, AND you get lots and lots of incredibly nutrient rich compost. I can grow corn in my backyard now in a foot of chicken manure compost (this was impossible when I was using soil I purchased).
Hope this helps!