I don’t know what size you are looking at. You can go to Home Depot, Lowe’s, or maybe a building supply or lumber yard and look at their prefab buildings. Find one that suits you in appearance and size. They’ll almost certainly erect it for you for a price.
You’ll have to do modifications, roosts, probably nests, and likely a pop door. You’ll have to add a lot of ventilation. In Florida heat can kill chickens. If you don’t want to do that yourself and don’t have a handyman, chat with the erectors. They may do that for you on the side. I suggest a wooden building. They are easier to work on and if you use a light color, don’t get as hot as a metal building.
Don’t forget you will need a foundation of some type to keep it up off the ground and away from termites. They may not provide a foundation for you. Cinder blocks, treated wood, or a concrete foundation will all work, but you need a way to attach the building to the foundation so a hurricane or thunderstorm doesn’t blow it away.
I also suggest you don’t get a floor. Use the ground. You said it was fairly dry, but maybe add a few inches of dirt or sand inside to raise that level even more.
Another option is to come up with a design and get a local contractor or handyman to build it for you from scratch. That way you don’t really have to coordinate anything. There might be some benefits if the guy doing the foundation has to put the building on top of it.
Good luck.
