A lot will depend on different variables. Right now I have 55 chickens in a coop with enough sq. footage for 40 chickens at 4 sq ft per bird. It's not really that cramped, and they have a grassy run. They are quarantined at the time being.
I have 16 in a coop that has enough sq. ft. for 40 chickens, and they are just as happy with the same setup as the previously mentioned chickens. They get one large scoop (horse feed scoop) of feed per day and greens from the garden, plus whatever free ranging they will do. A bag of feed for them lasts maybe 2-3 weeks.
I am not positive on certification. I would assume that to sell livestock, it is required, but since it's a hobby, you might be able to get away with it. There is lots of testing needed if you want to be NPIP certified, and certified organic I'm sure is the same.
As far as coop, 140 ft would give you the recommended 4 sq. ft per bird. So 10x14, but if you consider that most materials will come in 8 ft lengths, like plywood, you might want to consider 8x16. You would gain extra sq. footage, and wouldn't have any waste.
I could draw up some plans or you could just look at some on the coop designs page, but the number will throw you for a loop. Construction materials are pricey! Look for used if you can, check Craigslist or Freecycle. Also pallets have been used with great success. Use your imagination and what you have laying around. Will you be building this coop or having someone else build it? If you will be hiring someone, you can probably at least double the price of the materials for labor.
I know that some vaccinate for Mareks and I'm sure I've heard of another vaccine, although, I'm not sure if they would be required depending on how you plan on selling these chicks (pet quality/ show quality).
As far as I know, it's nearly impossible to make money with chickens. Even if you don't consider your start up costs (feeders, waterers, birds, coops, runs), you are still talking about feeding 35 birds. If you feed them cheap feed, you're still looking at $10 for 50 lbs at the least. They will probably go through that in a week or so. So from the start you are diving into the negatives. Do you plan on buying chicks to start with? Each chick say costs $2, and you need $35, so $70, and say on average you go through 50lbs every two weeks. And to get them to laying and breeding age, say 20 weeks. So you have $100 in feed at least to get them to laying age, and that's a VERY conservative estimate. Then the price would also go up tremendously if you were buying show quality chickens as well. You would want to feed them better feed, etc., but you could most likely sell chicks for a bit more. Will you be selling chicks as day old? or would you raise them to be a few weeks, etc.? Do you plan on incubating eggs? Then you are talking electricity usage, plus more time and energy, and your time is worth something, and even if it's not, it's still costing money. If you sell them as day olds, you won't have the food investment though. The chances of a broody barred rock are pretty slim, but I guess it could happen, but then your broody hen is no longer laying, so that's less chicks, which means less money, but a hen sitting on eggs, saves electricity and your time and energy. I just paid $1 each for chicks last night, and $2 each for 12-14 week old barred rocks. I'm sure they paid a lot more than that to feed them to get them to that age.
I am by no means trying to talk you out of something you want to do, please don't take it wrong. I have sat here pondering the exact same thing quite a few nights, trying to figure out how to make it work, and how to make money. I'm sure you could do it somehow. I have just found that chickens are a lot more expensive than I ever thought they would be.
