I kept two injured Silkie hens in the house for two months with just paper on the wood floor and some cardboard boxes for them to feel enclosed. They were great, except for the room it took up. We had no dog, then. We were home most of the time.
I kept rabbits out on my balcony when I lived in a no pets apartment years ago. 
City chickens are becoming a big thing! Check out chicken tractors. Some are commercial and built for small spaces. 
I would suggest, also, checking out smaller breeds than Silkies unless you have your heart set on the fluff ball.  I love my Belgian Quail and they are cute and small. Seremas are even smaller, but pricey for a chicken.  
If you are going to have only one or two birds, make sure they are hand raised, preferably by you...but then you won't know if they are he or she's when you get them. 
Ps There are predators in the city, so protect the girls, if you get them! 
Sorry this doesn't answer your question.