I know it's exciting, but I think maybe you should just take some time to learn more about chickens before you start a business. I don't want to hurt you feelings or anything, but heck, I've been doing this 5 years and still have no idea what I'm doing sometimes.
What exactly do you want to do? Sell eggs, sell hatching eggs, sell chicks, etc. etc. etc.?
I would also start out by saying, "Ok, I want to breed xxxx breed." And just start small with a few breeds, then when your established a little more and know what market your selling to, you can add more.
I would practice familiarizing myself with breeds and the anatomy of a chicken. At 5-6 months you should be able to tell if you have hens or roos.
And depending on how much you want to expand you'll probably want more than just one roo of the breed you're breeding. So, say you want to breed Rhode Island Reds. If you just have one roo, eventually the gene pools going to run thin, and you'll need some new blood in there. Do you know the difference between in-breeding and line breeding? In-breeding is a big no-no. That's crossing brothers and sisters, and you're going to run into some serious defects and deaths (ask me how I know). Line breeding is crossing moms and sons or fathers and daughters. It's okay, but you really want to avoid it if at all possible. So, really, it would be ideal to have a few different roos and hens too, then you could also breed ones that will compliment each other.
You also will need to tag all your birds, and keep good records. If you really want to sell purebreds, definitely no letting them all run together. If you're going to be breeding RIRs, you'll need to be able to know they're pure and who the mom and dad is.
Also, how is the one roo handicapped? If it's something genetic that could be passed to offspring, DON"T BREED HIM!! You'll just get more "bad stock" and you don't want that.
Where did your birds come from? If they're just normal hatchery stock, there's not much point in breeding, since all you'll get is more hatchery quality birds. You could keep them for yourself, or find someone who wouldn't mind, but I think real nice birds give you a better start. Sometimes you can get REALLY NICE hatchery birds though, and if you have that then go right ahead.
I would also familiarize myself with the APA standard of excellence, so that you are breeding birds as true to the standard as possible.
I'm honestly not trying to put you down or anything, but this is a pretty big commitment. I know how you feel, you really want to just go for it and do it, but it's going to take some prep, patience, and work.
~~Ms.B
P.S. There's lots of good info on here that will help you learn to distinguish roos from hens too.
