Yeah, you get so much stuff on how much space they need you just don’t know where to turn. Remember that a whole lot of the guidelines are geared toward people keeping 4 to 6 hens in a small backyard coop and totally enclosed run. They are intended to keep people out of trouble in almost all climates and are often overkill for a whole lot of us.
How much space they need depends on a whole lot of things. It does not matter if that space is in the coop, the coop and run, or they nest in trees and have the whole world to roam in. Your climate and how you manage them is mainly what determines how much space you need.
In Haiti, you are not worried about cold weather or snow at all. The danger is from the heat. I don’t know how hot it actually gets in Haiti, especially where they are. If they are fairly near the coast, they probably won’t see the temperatures the interior of the US gets because of the moderating effects of the ocean, but it will often get steamy. I’d still assume it will get hot enough to kill them.
If all you need the coop for is a place for them to sleep at night and lay eggs, you don’t need much room, basically just enough for them to roost. For this to work, you need to make sure they are not locked in there for much time after they wake up. That’s where management comes in. I generally recommend some extra room on the roosts, such as 12” per chicken, but in your case I think you can go with less, more like 9” per chicken. It’s not that they take up 9” of roost space when they have settled in on the roost, but they need extra space to get up to the roosts and position themselves for the night.
With large numbers of chickens, they don’t need as much room per chicken as small numbers, either on the roosts or in the coop. I’ll try to explain. I know these numbers are not realistic but I’m using whole numbers to make the math easier. It’s the concept I’m after.
Assume a chicken occupies 1 square feet of space when it is on the coop floor. Give each chicken the rule of thumb 4 square feet of space. If you have 4 chickens, they have 16 square feet of coop space and occupy 4 of those. That leaves 12 square feet unoccupied for them to explore.
Now go with 40 chickens still each having 4 square feet. They are going to occupy 40 square feet but have 160 square feet of coop space. That leaves them 120 square feet to explore. There is a whole lot of difference there.
As far as building the coop, you are not worried about anything related to cold. Your concern is almost certainly thunderstorms and hurricanes. Wind and driving rain. Position the coop where it won’t flood.
With heat being the danger, think open air coops so you get plenty of ventilation. At least one wall needs to be wire, not solid. I’d give a whole lot of consideration to just building a wire building with a roof to stop rain from falling on them and sort of boxing in the roosts one three sides to prevent those storm winds from hitting them on the roosts. Have wire below and above that “boxed-in” section. That should keep your costs down and allow the wind to go through except where the chickens are roosting. That would reduce the wind force on the building a lot.
Normally I’d say you need to have a place to keep the chicken feed dry, but those people are probably not going to be able to afford to buy chicken feed. In those types of climates chickens have been foraging for all their food for thousands of years. They are quite capable of finding their own food. That brings up another possible issue though.
How do they keep the chickens out of their gardens? I’ll assume they are raising a lot of their own food in gardens. Can they afford fences? I think before you go to all this trouble and expense, someone needs to talk to them about how they will manage them. I’ve worked overseas in some pretty poor countries. I’ve seen the big multinational companies provide some pretty nice things for the locals that are a total waste because the people either don’t have the expertise to manage what they are given (A modern dental clinic, for example) or more often, don’t have the money it takes to operate it. When we put computers in a local school in Kazakhstan we also paid for two years’ worth of electricity so the kids could operate them.
As far as breed, you don’t need a breed. A barnyard mix will do nicely. Plenty of people there raise chickens that are acclimated to the area and produce eggs and meat. You can eat any chicken. Buy chickens from someone local. They will probably really like the cash. Of course, you need someone with a bit of expertise in chickens to buy them, otherwise you are likely to overpay good money for someone’s rejects. Those people may be poor but they are not dumb. They’ll take advantage of the situation if they can. When you are struggling to feed your family your principles are geared more to taking every advantage offered instead of being a nice guy.
I applaud you on this effort. It can make a difference but I hope the details have been worked out so it is a workable solution to the problem. I know it is a huge problem down there in one of the poorest places on earth.