I've done small scale selling chicks, not enough to really make any profit. Mostly just to support my hatching addiction
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This is where your local market needs to be taken into account. I have several feed stores in my local area that sell chicks basically from Feb-June, and again Sept-Nov. They order sexed pullets from the large hatcheries and sell them for between $2-5 each depending on the breed. They offer a decent variety of breeds, including some not-so-common birds. That's hard for me to compete with. I can't accurately vent sex chicks, so I'd have to sell straight run or breed sex links. I worked on a blue egg laying blue sex link for two years before throwing in the towel. To compete with the local feed stores, I'll need to offer something unique, preferably in a sex link so I can guarantee pullets. Most folks around here don't want straight run. The other option is to grow them out to 6ish weeks when they can be sexed fairly accurately and offer a pullet guarantee. That does leave me with a bunch of cockerels to either sell off or raise up and butcher. You also need more space than if you're selling chicks as day-olds.
Some areas don't have so much competition from the feed stores, that would be a bonus for you.
Some areas folks might not mind buying straight run. I've had a few folks not mind, but most want pullets.
You also need to take into account the cost of your incubator, and your hatch rates. Incubating has a definite learning curve. Even finding a used styrobator on CL with a turner (I've seen them here for around $60), you'd have to hatch and sell several chicks just to cover the cost of the incubator. Then you have the brooder, electricity for the light or heating pad, starter feed, etc.
added--I was typing when the above response came in. I also sell point of lay pullets and they are probably the best money makers. Thing is, you have to have housing for them up til 5ish months of age.