I highly suggest getting a chicken to make your tiny farm complete. They'll help eat bugs, are easier to maintain than a cat or dog, and seriously...they're awesome. Plus, you get free, organic eggs!
I grew up with chickens, and I agree with you that they are awesome. I think my current yard is simply too small for a chicken - it's about 200 square feet total, and 100 square feet is patio. I don't think chickens are happy on their own, so I'd need at least 2. They'd need a pen of some sort, which would reduce my garden space.
I've thought about it, and it's sadly not workable for me right now.
But in my next yard! I'll definitely have chickens.