I just wanted to second whoever said there are always predators.....this is very true.
I have 3 chickens in an urban neighborhood. We have a secure 8' privacy fence, and we have raccoons, skunks, possums and snakes in the yard almost every night. During the day we have hawks, who are brazen in their hunting if they think they can get away with it! I never leave my chickens out in the yard unattended for more than a couple minutes at a time.
If you only clean your chickens once or twice a week, yes, you will have trouble with stink. I clean my coop (6'x6' kids' playhouse) at least once and sometimes twice a day, and that keeps the smell at bay, but just barely.
I would never EVER trust a dog around chickens. Ever. It's just asking for trouble, IMO. Dogs are ruled by instinct, no matter how well-trained they are.
This probably won't be a popular answer, but I don't think you should get chickens if your wife doesn't want them. They are more work than you might expect, and I would treat them as you would any other major decision. You should be in agreement with each other before jumping in.
Get some good chicken books and see if she will read them with you. Maybe she'll change her mind, and then you can both participate and have fun with chickens.
I have SO enjoyed my 3 girls, and they have been a ton of fun for our whole family, but they do take work and time, and we can't really travel far because we don't know anyone who would care for them more than a couple times in a few days.