Welcome to BYC
May i ask why you are looking to get only one chicken? Chickens are flock animals, therefor do not thrive as a loner. They can be a loner, but they are unhappy. I've seen people with just one hen, and boy do they look so miserable and lonely. Its not wise to get only one, therefor if you really want healthy and striving chickens you are much better getting 2 or 3 Bantam Silkies. Try searching for breeders in your town or on craiglist. If your away alot during the day, shes going to be lonely without chicken company.
Im going to ask another question.... why are you wanting chickens? Egg production? Or a pet? Bantam Silkies go broody more than often and you might not get the best egg productions. So if egg production is what you want try Rhode Island reds...but they needed a reasonably big area. If you want her as a pet, Bantam silkies will do great. However as i stated before, you will be better of getting more than one..
If you want my advice, that cage wont be very comfortable even for a small hen like her....if you can spend a bit of $ try a large dog crate...you can find them pretty much everywhere
If shes going to be locked up for a while during the day, she needs a reasonably good size...
Good luck
-Mustang