HEY! I'm in Seattle too!
And I can tell you what you probably already know:
You can keep three fowl on a standard city lot; for every 1000 square feet above the minumum lot requirement of 5,000 square feet, you can keep an additional fowl.
This can be ducks, peafowl, geese or whatever. And please note that this includes ROOSTERS. All these people were telling me you can't keep roos in Seattle city limits. This is false. There is nothing in Seattle Municipal Code that says otherwise, but to be sure, I called the city clerk's office. And yes, you can keep a rooster.
She did add that your neighbor's can complain about the noise. Here is what Seattle City Code has to say about this:
25.08.500 Public disturbance noises.
It is unlawful for any person knowingly to cause or make, or for any person in possession of property knowingly to allow or originate from the property, unreasonable noise which disturbs another, and to refuse or intentionally fail to cease the unreasonable noise when ordered to do so by a police officer or, pursuant to subsection A of this section, when ordered to do so by a police officer or animal control officer. Unreason-able noise shall include the following sounds or combination of sounds:
A. Loud and raucous, and frequent, repetitive, or continuous sounds made by any animal, except that such sounds made in animal shelters, commercial kennels, veterinary hospitals, pet shops, or pet kennels licensed under and in compliance with Chapter 10.72 of this Code shall be exempt from this subsection; provided, that notwithstanding any other provision of this chapter, if the owner or other person having cus-tody of the animal cannot, with reasonable inquiry, be located by the investigating officer or if the animal is a repeated violator of this subsection, the animal shall be impounded by the poundmaster, subject to re-demption in the manner provided by Chapter 9.08 of this Code;
As you can see, the law does not treat noise coming from livestock differently than noise coming from pets. Would you ask her opinion before getting a dog? Probably not--even though we all know that the dog barking chain can be a HUGE source of noise. This is about perception.
All this is to say that your neighbor needs to suck it up. I think you're being very nice and considerate, and kudos to you for that. It's always better to be on good terms with neighbors. Ultimately, however, I wouldn't let her opinions interfere with getting chickens if you want them, nor would I let them dictate where on your property you build your coop.