Whatever you end up getting, MAKE SURE you have enough space for them. Minimum of 4 sq ft floorspace in the coop per chicken, and minimum of 10 sq feet in the run per chicken. Some breeds/individuals need more space than that. This will help prevent behavior issues and stress.
Have a plan for poop management. Have a plan for predator control in place as you build your coop/run, and before you get the chickens. Everything likes to eat chicken.
Have a biosecurity plan and biosecurity measures in place before you start out - once disease gets into your flock it may not be possible to get it out of your land, depending on what it is. Consider where you're getting your chickens from and what controls are in place as far as health, wellness, and biosecurity goes.
You've probably thought of these things, but if not, I wanted to mention them.
I keep 15 laying hens that give (before my one hen went broody) 12-14 eggs a day. I sell 4 dozen a week and have 2 dozen for my family. I keep a dozen or partial dozen in reserve because there's occasionally cracked eggs or dented eggs, or ugly or dirty eggs that I can't sell and don't want to eat - I feed them back to the chickens. Selling 4 dozen a week pays for chicken feed. Not for the effort I put into washing the eggs, collecting the eggs, caring for the hens, medicine, maybe not even much of the cost of egg cartons, if the customers don't bring them back. I can't raise prices because that's what eggs sell for in my area. If I go organic or non-GMO my feed costs increase, but in order to reach the buyers that would pay more for non-GMO or organic eggs, I'd have to rent a booth at the farmers market, and all the egg sales money would go towards booth rental instead of chicken feed.
Really do some calculations first before you think you might sell eggs and make a profit to be sure you know what you're getting into. In my experience (which granted is only a year or so), eggs are more of an add-on to whatever a vendor is selling at the farmers market, be it meat, or vegetables, or home crafts, etc. The make the rental fees by selling high dollar items, and the eggs are more of a maximizing revenue option. For me, there's really no profit in it, I do it for fun, and to cover feed costs. The volume of hens, eggs, and management style, and permits I'd need to do commercial egg production, and the time involved, are not something I can support.