I agree with Chuck - one more tip to keep things simple - decide how many you want in your first flock and get all of them at once. Don't make the same mistake as I did, and decide you've got room for another one, a week or two after getting the first lot, or the poor little girl may have a hard time of it when she arrives.
Also, if you get a batch of hybrids of mixed breeds, not only do they look more interesting in the run, and are easier to tell apart, but they'll each lay an egg of different colours and sizes, so easy to tell who's been a good girl that day!